< draft-ietf-manet-dlep-14.txt   draft-ietf-manet-dlep-15.txt >
Mobile Ad hoc Networks Working Group S. Ratliff Mobile Ad hoc Networks Working Group S. Ratliff
Internet-Draft VT iDirect Internet-Draft VT iDirect
Intended status: Standards Track B. Berry Intended status: Standards Track B. Berry
Expires: November 14, 2015 Expires: January 7, 2016
S. Jury S. Jury
Cisco Systems Cisco Systems
D. Satterwhite D. Satterwhite
Broadcom Broadcom
R. Taylor R. Taylor
Airbus Defence & Space Airbus Defence & Space
May 13, 2015 July 6, 2015
Dynamic Link Exchange Protocol (DLEP) Dynamic Link Exchange Protocol (DLEP)
draft-ietf-manet-dlep-14 draft-ietf-manet-dlep-15
Abstract Abstract
When routing devices rely on modems to effect communications over When routing devices rely on modems to effect communications over
wireless links, they need timely and accurate knowledge of the wireless links, they need timely and accurate knowledge of the
characteristics of the link (speed, state, etc.) in order to make characteristics of the link (speed, state, etc.) in order to make
routing decisions. In mobile or other environments where these routing decisions. In mobile or other environments where these
characteristics change frequently, manual configurations or the characteristics change frequently, manual configurations or the
inference of state through routing or transport protocols does not inference of state through routing or transport protocols does not
allow the router to make the best decisions. A bidirectional, event- allow the router to make the best decisions. A bidirectional, event-
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material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 14, 2015. This Internet-Draft will expire on January 7, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Protocol Overview . . . . . . . . . . . . . . . . . . . . 7 1.1. Protocol Overview . . . . . . . . . . . . . . . . . . . . 7
1.2. Requirements . . . . . . . . . . . . . . . . . . . . . . 8 1.2. Requirements . . . . . . . . . . . . . . . . . . . . . . 8
2. Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . 8 2. Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . 8
3. Core Features and Optional Extensions . . . . . . . . . . . . 10 3. Core Features and Extensions . . . . . . . . . . . . . . . . 10
3.1. Negotiation of Optional Extensions . . . . . . . . . . . 10 3.1. Experiments . . . . . . . . . . . . . . . . . . . . . . . 10
3.2. Protocol Extensions . . . . . . . . . . . . . . . . . . . 11
3.3. Experimental Signals and Data Items . . . . . . . . . . . 11
4. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1. Mandatory Metrics . . . . . . . . . . . . . . . . . . . . 12 4.1. Mandatory Metrics . . . . . . . . . . . . . . . . . . . . 12
5. DLEP Session Flow . . . . . . . . . . . . . . . . . . . . . . 12 5. DLEP Session Flow . . . . . . . . . . . . . . . . . . . . . . 12
5.1. DLEP Router session flow - Discovery case . . . . . . . . 13 5.1. Peer Discovery State . . . . . . . . . . . . . . . . . . 12
5.2. DLEP Router session flow - Configured case . . . . . . . 13 5.2. Session Initialization State . . . . . . . . . . . . . . 13
5.3. DLEP Modem session flow . . . . . . . . . . . . . . . . . 14 5.3. In-Session State . . . . . . . . . . . . . . . . . . . . 14
5.4. Common Session Flow . . . . . . . . . . . . . . . . . . . 15 5.4. Session Termination State . . . . . . . . . . . . . . . . 16
6. DLEP Signal Structure and Processing . . . . . . . . . . . . 16 6. DLEP Signal and Message Processing . . . . . . . . . . . . . 16
6.1. DLEP Signal Header . . . . . . . . . . . . . . . . . . . 16 7. DLEP Signal and Message Structure . . . . . . . . . . . . . . 17
6.2. DLEP Generic Data Item . . . . . . . . . . . . . . . . . 17 7.1. DLEP Signal Header . . . . . . . . . . . . . . . . . . . 18
7. DLEP Signals . . . . . . . . . . . . . . . . . . . . . . . . 17 7.2. DLEP Message Header . . . . . . . . . . . . . . . . . . . 18
7.1. Peer Discovery Signal . . . . . . . . . . . . . . . . . . 18 7.3. DLEP Generic Data Item . . . . . . . . . . . . . . . . . 19
7.2. Peer Offer Signal . . . . . . . . . . . . . . . . . . . . 19 8. DLEP Signals and Messages . . . . . . . . . . . . . . . . . . 19
7.3. Peer Initialization Signal . . . . . . . . . . . . . . . 19 8.1. Peer Discovery Signal . . . . . . . . . . . . . . . . . . 20
7.4. Peer Initialization ACK Signal . . . . . . . . . . . . . 20 8.2. Peer Offer Signal . . . . . . . . . . . . . . . . . . . . 21
7.5. Peer Update Signal . . . . . . . . . . . . . . . . . . . 22 8.3. Session Initialization Message . . . . . . . . . . . . . 21
7.6. Peer Update ACK Signal . . . . . . . . . . . . . . . . . 23 8.4. Session Initialization Response Message . . . . . . . . . 22
7.7. Peer Termination Signal . . . . . . . . . . . . . . . . . 24 8.5. Session Update Message . . . . . . . . . . . . . . . . . 24
7.8. Peer Termination ACK Signal . . . . . . . . . . . . . . . 25 8.6. Session Update Response Message . . . . . . . . . . . . . 25
7.9. Destination Up Signal . . . . . . . . . . . . . . . . . . 25 8.7. Session Termination Message . . . . . . . . . . . . . . . 25
7.10. Destination Up ACK Signal . . . . . . . . . . . . . . . . 26 8.8. Session Termination Response Message . . . . . . . . . . 26
7.11. Destination Down Signal . . . . . . . . . . . . . . . . . 27 8.9. Destination Up Message . . . . . . . . . . . . . . . . . 26
7.12. Destination Down ACK Signal . . . . . . . . . . . . . . . 27 8.10. Destination Up Response Message . . . . . . . . . . . . . 27
7.13. Destination Update Signal . . . . . . . . . . . . . . . . 28 8.11. Destination Down Message . . . . . . . . . . . . . . . . 28
7.14. Heartbeat Signal . . . . . . . . . . . . . . . . . . . . 29 8.12. Destination Down Response Message . . . . . . . . . . . . 28
7.15. Link Characteristics Request Signal . . . . . . . . . . . 29 8.13. Destination Update Message . . . . . . . . . . . . . . . 29
7.16. Link Characteristics ACK Signal . . . . . . . . . . . . . 30 8.14. Heartbeat Message . . . . . . . . . . . . . . . . . . . . 30
8. DLEP Data Items . . . . . . . . . . . . . . . . . . . . . . . 31 8.15. Link Characteristics Request Message . . . . . . . . . . 30
8.1. DLEP Version . . . . . . . . . . . . . . . . . . . . . . 32 8.16. Link Characteristics Response Message . . . . . . . . . . 31
8.2. Status . . . . . . . . . . . . . . . . . . . . . . . . . 33 9. DLEP Data Items . . . . . . . . . . . . . . . . . . . . . . . 32
8.3. IPv4 Connection Point . . . . . . . . . . . . . . . . . . 34 9.1. Status . . . . . . . . . . . . . . . . . . . . . . . . . 33
8.4. IPv6 Connection Point . . . . . . . . . . . . . . . . . . 35 9.2. IPv4 Connection Point . . . . . . . . . . . . . . . . . . 35
8.5. Peer Type . . . . . . . . . . . . . . . . . . . . . . . . 36 9.3. IPv6 Connection Point . . . . . . . . . . . . . . . . . . 36
8.6. Heartbeat Interval . . . . . . . . . . . . . . . . . . . 36 9.4. Peer Type . . . . . . . . . . . . . . . . . . . . . . . . 37
8.7. Extensions Supported . . . . . . . . . . . . . . . . . . 37 9.5. Heartbeat Interval . . . . . . . . . . . . . . . . . . . 38
8.8. Experimental Definition . . . . . . . . . . . . . . . . . 38 9.6. Extensions Supported . . . . . . . . . . . . . . . . . . 39
8.9. MAC Address . . . . . . . . . . . . . . . . . . . . . . . 38 9.7. MAC Address . . . . . . . . . . . . . . . . . . . . . . . 39
8.10. IPv4 Address . . . . . . . . . . . . . . . . . . . . . . 39 9.8. IPv4 Address . . . . . . . . . . . . . . . . . . . . . . 40
8.11. IPv6 Address . . . . . . . . . . . . . . . . . . . . . . 40 9.9. IPv6 Address . . . . . . . . . . . . . . . . . . . . . . 41
8.12. IPv4 Attached Subnet . . . . . . . . . . . . . . . . . . 40 9.10. IPv4 Attached Subnet . . . . . . . . . . . . . . . . . . 42
8.13. IPv6 Attached Subnet . . . . . . . . . . . . . . . . . . 41 9.11. IPv6 Attached Subnet . . . . . . . . . . . . . . . . . . 42
8.14. Maximum Data Rate (Receive) . . . . . . . . . . . . . . . 42 9.12. Maximum Data Rate (Receive) . . . . . . . . . . . . . . . 43
8.15. Maximum Data Rate (Transmit) . . . . . . . . . . . . . . 43 9.13. Maximum Data Rate (Transmit) . . . . . . . . . . . . . . 44
8.16. Current Data Rate (Receive) . . . . . . . . . . . . . . . 43 9.14. Current Data Rate (Receive) . . . . . . . . . . . . . . . 44
8.17. Current Data Rate (Transmit) . . . . . . . . . . . . . . 44 9.15. Current Data Rate (Transmit) . . . . . . . . . . . . . . 45
8.18. Latency . . . . . . . . . . . . . . . . . . . . . . . . . 45 9.16. Latency . . . . . . . . . . . . . . . . . . . . . . . . . 46
8.19. Resources (Receive) . . . . . . . . . . . . . . . . . . . 46 9.17. Resources (Receive) . . . . . . . . . . . . . . . . . . . 47
8.20. Resources (Transmit) . . . . . . . . . . . . . . . . . . 46 9.18. Resources (Transmit) . . . . . . . . . . . . . . . . . . 47
8.21. Relative Link Quality (Receive) . . . . . . . . . . . . . 47 9.19. Relative Link Quality (Receive) . . . . . . . . . . . . . 48
8.22. Relative Link Quality (Transmit) . . . . . . . . . . . . 48 9.20. Relative Link Quality (Transmit) . . . . . . . . . . . . 49
8.23. Link Characteristics ACK Timer . . . . . . . . . . . . . 48 9.21. Link Characteristics Response Timer . . . . . . . . . . . 49
9. Credit-Windowing . . . . . . . . . . . . . . . . . . . . . . 49 10. Credit-Windowing . . . . . . . . . . . . . . . . . . . . . . 50
9.1. Credit-Windowing Signals . . . . . . . . . . . . . . . . 49 10.1. Credit-Windowing Messages . . . . . . . . . . . . . . . 51
9.1.1. Destination Up Signal . . . . . . . . . . . . . . . . 49 10.1.1. Destination Up Message . . . . . . . . . . . . . . . 51
9.1.2. Destination Up ACK Signal . . . . . . . . . . . . . . 50 10.1.2. Destination Up Response Message . . . . . . . . . . 51
9.1.3. Destination Update Signal . . . . . . . . . . . . . . 50 10.1.3. Destination Update Message . . . . . . . . . . . . . 51
9.2. Credit-Windowing Data Items . . . . . . . . . . . . . . . 50 10.2. Credit-Windowing Data Items . . . . . . . . . . . . . . 52
9.2.1. Credit Grant . . . . . . . . . . . . . . . . . . . . 51 10.2.1. Credit Grant . . . . . . . . . . . . . . . . . . . . 52
9.2.2. Credit Window Status . . . . . . . . . . . . . . . . 52 10.2.2. Credit Window Status . . . . . . . . . . . . . . . . 53
9.2.3. Credit Request . . . . . . . . . . . . . . . . . . . 52 10.2.3. Credit Request . . . . . . . . . . . . . . . . . . . 54
10. Security Considerations . . . . . . . . . . . . . . . . . . . 53 11. Security Considerations . . . . . . . . . . . . . . . . . . . 55
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 53 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 55
11.1. Registrations . . . . . . . . . . . . . . . . . . . . . 53 12.1. Registrations . . . . . . . . . . . . . . . . . . . . . 55
11.2. Expert Review: Evaluation Guidelines . . . . . . . . . . 54 12.2. Expert Review: Evaluation Guidelines . . . . . . . . . . 56
11.3. Signal Type Registration . . . . . . . . . . . . . . . . 54 12.3. Signal/Message Type Registration . . . . . . . . . . . . 56
11.4. DLEP Data Item Registrations . . . . . . . . . . . . . . 55 12.4. DLEP Data Item Registrations . . . . . . . . . . . . . . 56
11.5. DLEP Status Code Registrations . . . . . . . . . . . . . 56 12.5. DLEP Status Code Registrations . . . . . . . . . . . . . 56
11.6. DLEP Extensions Registrations . . . . . . . . . . . . . 56 12.6. DLEP Extensions Registrations . . . . . . . . . . . . . 56
11.7. DLEP Well-known Port . . . . . . . . . . . . . . . . . . 57 12.7. DLEP Well-known Port . . . . . . . . . . . . . . . . . . 57
11.8. DLEP Multicast Address . . . . . . . . . . . . . . . . . 57 12.8. DLEP Multicast Address . . . . . . . . . . . . . . . . . 57
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 57 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 57
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 57 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 57
13.1. Normative References . . . . . . . . . . . . . . . . . . 57 14.1. Normative References . . . . . . . . . . . . . . . . . . 57
13.2. Informative References . . . . . . . . . . . . . . . . . 57 14.2. Informative References . . . . . . . . . . . . . . . . . 57
Appendix A. Peer Level Signal Flows . . . . . . . . . . . . . . 57 Appendix A. Discovery Signal Flows . . . . . . . . . . . . . . . 58
A.1. Discovery . . . . . . . . . . . . . . . . . . . . . . . . 57 Appendix B. Peer Level Message Flows . . . . . . . . . . . . . . 58
A.2. Session Initialization . . . . . . . . . . . . . . . . . 58 B.1. Session Initialization . . . . . . . . . . . . . . . . . 58
A.3. Session Initialization - Refused . . . . . . . . . . . . 59 B.2. Session Initialization - Refused . . . . . . . . . . . . 59
A.4. Router Changes IP Addresses . . . . . . . . . . . . . . . 59 B.3. Router Changes IP Addresses . . . . . . . . . . . . . . . 59
A.5. Modem Changes Session-wide Metrics . . . . . . . . . . . 59 B.4. Modem Changes Session-wide Metrics . . . . . . . . . . . 59
A.6. Router Terminates Session . . . . . . . . . . . . . . . . 60 B.5. Router Terminates Session . . . . . . . . . . . . . . . . 60
A.7. Modem Terminates Session . . . . . . . . . . . . . . . . 60 B.6. Modem Terminates Session . . . . . . . . . . . . . . . . 60
A.8. Session Heartbeats . . . . . . . . . . . . . . . . . . . 61 B.7. Session Heartbeats . . . . . . . . . . . . . . . . . . . 61
A.9. Router Detects a Heartbeat timeout . . . . . . . . . . . 62 B.8. Router Detects a Heartbeat timeout . . . . . . . . . . . 62
A.10. Modem Detects a Heartbeat timeout . . . . . . . . . . . . 63 B.9. Modem Detects a Heartbeat timeout . . . . . . . . . . . . 63
Appendix B. Destination Specific Signal Flows . . . . . . . . . 63 Appendix C. Destination Specific Signal Flows . . . . . . . . . 63
B.1. Common Destination Signaling . . . . . . . . . . . . . . 63 C.1. Common Destination Signaling . . . . . . . . . . . . . . 63
B.2. Multicast Destination Signaling . . . . . . . . . . . . . 64 C.2. Multicast Destination Signaling . . . . . . . . . . . . . 64
B.3. Link Characteristics Request . . . . . . . . . . . . . . 64 C.3. Link Characteristics Request . . . . . . . . . . . . . . 64
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 65 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 65
1. Introduction 1. Introduction
There exist today a collection of modem devices that control links of There exist today a collection of modem devices that control links of
variable datarate and quality. Examples of these types of links variable datarate and quality. Examples of these types of links
include line-of-sight (LOS) terrestrial radios, satellite terminals, include line-of-sight (LOS) terrestrial radios, satellite terminals,
and cable/DSL modems. Fluctuations in speed and quality of these and cable/DSL modems. Fluctuations in speed and quality of these
links can occur due to configuration, or on a moment-to-moment basis, links can occur due to configuration, or on a moment-to-moment basis,
due to physical phenomena like multipath interference, obstructions, due to physical phenomena like multipath interference, obstructions,
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| | | Device| | Device| | | | | | Device| | Device| | |
+--------+ +-------+ +-------+ +--------+ +--------+ +-------+ +-------+ +--------+
| | | Link | | | | | | Link | | |
|-DLEP--| | Protocol | |-DLEP--| |-DLEP--| | Protocol | |-DLEP--|
| | | (e.g. | | | | | | (e.g. | | |
| | | 802.11) | | | | | | 802.11) | | |
Figure 1: DLEP Network Figure 1: DLEP Network
In Figure 1, when the local modem detects the presence of a remote In Figure 1, when the local modem detects the presence of a remote
node, it (the local modem) sends a signal to its router via the DLEP node, it (the local modem) sends a message to its router via the DLEP
protocol. The signal consists of an indication of what change has protocol. The message consists of an indication of what change has
occurred on the link (e.g., presence of a remote node detected), occurred on the link (e.g., presence of a remote node detected),
along with a collection of DLEP-defined Data Items that further along with a collection of DLEP-defined Data Items that further
describe the change. Upon receipt of the signal, the local router describe the change. Upon receipt of the message, the local router
may take whatever action it deems appropriate, such as initiating may take whatever action it deems appropriate, such as initiating
discovery protocols, and/or issuing HELLO messages to converge the discovery protocols, and/or issuing HELLO messages to converge the
network. On a continuing, as-needed basis, the modem devices use network. On a continuing, as-needed basis, the modem devices use
DLEP to report any characteristics of the link (datarate, latency, DLEP to report any characteristics of the link (datarate, latency,
etc.) that have changed. DLEP is independent of the link type and etc.) that have changed. DLEP is independent of the link type and
topology supported by the modem. Note that the DLEP protocol is topology supported by the modem. Note that the DLEP protocol is
specified to run only on the local link between router and modem. specified to run only on the local link between router and modem.
Some over the air signaling may be necessary between the local and Some over the air signaling may be necessary between the local and
remote modem in order to provide some parameters in DLEP signals remote modem in order to provide some parameters in DLEP messages
between the local modem and local router, but DLEP does not specify between the local modem and local router, but DLEP does not specify
how such over the air signaling is carried out. Over the air how such over the air signaling is carried out. Over the air
signaling is purely a matter for the modem implementer. signaling is purely a matter for the modem implementer.
Figure 2 shows how DLEP can support a configuration where routers are Figure 2 shows how DLEP can support a configuration where routers are
connected with different link types. In this example, Modem A connected with different link types. In this example, Modem A
implements a point-to-point link, and Modem B is connected via a implements a point-to-point link, and Modem B is connected via a
shared medium. In both cases, the DLEP protocol is used to report shared medium. In both cases, the DLEP protocol is used to report
the characteristics of the link (datarate, latency, etc.) to routers. the characteristics of the link (datarate, latency, etc.) to routers.
The modem is also able to use the DLEP session to notify the router The modem is also able to use the DLEP session to notify the router
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| |
+---+----+ +---+----+
| Router | | Router |
| | | |
+--------+ +--------+
Figure 2: DLEP Network with Multiple Modem Devices Figure 2: DLEP Network with Multiple Modem Devices
1.1. Protocol Overview 1.1. Protocol Overview
As mentioned earlier, DLEP defines a set of signals used by modems As mentioned earlier, DLEP defines a set of messages used by modems
and their attached routers. The signals are used to communicate and their attached routers. The messages are used to communicate
events that occur on the physical link(s) managed by the modem: for events that occur on the physical link(s) managed by the modem: for
example, a remote node entering or leaving the network, or that the example, a remote node entering or leaving the network, or that the
link has changed. Associated with these signals are a set of data link has changed. Associated with these messages are a set of data
items - information that describes the remote node (e.g., address items - information that describes the remote node (e.g., address
information), and/or the characteristics of the link to the remote information), and/or the characteristics of the link to the remote
node. node.
The protocol is defined as a collection of type-length-value (TLV) The protocol is defined as a collection of type-length-value (TLV)
based formats, specifying the signals that are exchanged between a based formats, specifying the messages that are exchanged between a
router and a modem, and the data items associated with the signal. router and a modem, and the data items associated with the message.
This document specifies transport of DLEP signals and data items via This document specifies transport of DLEP messages and data items via
the TCP transport, with a UDP-based discovery mechanism. Other the TCP transport, with a UDP-based discovery mechanism. Other
transports for the protocol are possible, but are outside the scope transports for the protocol are possible, but are outside the scope
of this document. of this document.
DLEP uses a session-oriented paradigm between the modem device and DLEP uses a session-oriented paradigm between the modem device and
its associated router. If multiple modem devices are attached to a its associated router. If multiple modem devices are attached to a
router (as in Figure 2), or the modem supports multiple connections router (as in Figure 2), or the modem supports multiple connections
(via multiple logical or physical interfaces), then separate DLEP (via multiple logical or physical interfaces), then separate DLEP
sessions exist for each modem or connection. This router/modem sessions exist for each modem or connection. This router/modem
session provides a carrier for information exchange concerning session provides a carrier for information exchange concerning
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"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14, RFC 2119 [RFC2119]. 14, RFC 2119 [RFC2119].
2. Assumptions 2. Assumptions
Routers and modems that exist as part of the same node (e.g., that Routers and modems that exist as part of the same node (e.g., that
are locally connected) can use a discovery technique to locate each are locally connected) can use a discovery technique to locate each
other, thus avoiding a priori configuration. The router is other, thus avoiding a priori configuration. The router is
responsible for initializing the discovery process, using the Peer responsible for initializing the discovery process, using the Peer
Discovery signal (Section 7.1). Discovery signal (Section 8.1).
DLEP uses a session-oriented paradigm. A router and modem form a DLEP uses a session-oriented paradigm. A router and modem form a
session by completing the discovery and initialization process. This session by completing the discovery and initialization process. This
router-modem session persists unless or until it either (1) times router-modem session persists unless or until it either (1) times
out, based on the timeout values supplied, or (2) is explicitly torn out, based on the timeout values supplied, or (2) is explicitly torn
down by one of the participants. Note that while use of timers in down by one of the participants. Note that while use of timers in
DLEP is optional, it is strongly RECOMMENDED that implementations DLEP is optional, it is strongly RECOMMENDED that implementations
choose to run with timers enabled. choose to run with timers enabled.
DLEP assumes that the MAC address for delivering data traffic is the DLEP assumes that the MAC address for delivering data traffic is the
MAC specified in the Destination Up signal (Section 7.9). No MAC specified in the Destination Up message (Section 8.9). No
manipulation or substitution is performed; the MAC address supplied manipulation or substitution is performed; the MAC address supplied
in Destination Up is used as the OSI Layer 2 Destination MAC address. in Destination Up is used as the OSI Layer 2 Destination MAC address.
DLEP also assumes that MAC addresses MUST be unique within the DLEP also assumes that MAC addresses MUST be unique within the
context of a router-modem session. Additionally, DLEP can support context of a router-modem session. Additionally, DLEP can support
MAC addresses in either EUI-48 or EUI-64 format, with the restriction MAC addresses in either EUI-48 or EUI-64 format, with the restriction
that ALL MAC addresses for a given DLEP session MUST be in the same that ALL MAC addresses for a given DLEP session MUST be in the same
format, and MUST be consistent with the MAC address format of the format, and MUST be consistent with the MAC address format of the
connected modem (e.g., if the modem is connected to the router with connected modem (e.g., if the modem is connected to the router with
an EUI-48 MAC, all destination addresses via that modem MUST be an EUI-48 MAC, all destination addresses via that modem MUST be
expressed in EUI-48 format). expressed in EUI-48 format).
DLEP uses UDP multicast for single-hop discovery, and TCP for DLEP uses UDP multicast for single-hop discovery signalling, and TCP
transport of the control signals. Therefore, DLEP assumes that the for transport of the control messages. Therefore, DLEP assumes that
modem and router have topologically consistent IP addresses assigned. the modem and router have topologically consistent IP addresses
It is RECOMMENDED that DLEP implementations utilize IPv6 link-local assigned. It is RECOMMENDED that DLEP implementations utilize IPv6
addresses to reduce the administrative burden of address assignment. link-local addresses to reduce the administrative burden of address
assignment.
Destinations can be identified by either the router or the modem, and Destinations can be identified by either the router or the modem, and
represent a specific destination (e.g., an address) that exists on represent a specific destination (e.g., an address) that exists on
the link(s) managed by the modem. A destination MUST contain a MAC the link(s) managed by the modem. A destination MUST contain a MAC
address, it MAY optionally include a Layer 3 address (or addresses). address, it MAY optionally include a Layer 3 address (or addresses).
Note that since a destination is a MAC address, the MAC could Note that since a destination is a MAC address, the MAC could
reference a logical destination, as in a derived multicast MAC reference a logical destination, as in a derived multicast MAC
address, as well as a physical device. As destinations are address, as well as a physical device. As destinations are
discovered, DLEP routers and modems build an information base on discovered, DLEP routers and modems build an information base on
destinations accessible via the modem. destinations accessible via the modem.
The DLEP signals concerning destinations thus become the way for The DLEP messages concerning destinations thus become the way for
routers and modems to maintain, and notify each other about, an routers and modems to maintain, and notify each other about, an
information base representing the physical and logical (e.g., information base representing the physical and logical (e.g.,
multicast) destinations accessible via the modem device. The multicast) destinations accessible via the modem device. The
information base would contain addressing information (i.e. MAC information base would contain addressing information (i.e. MAC
address, and OPTIONALLY, Layer 3 addresses), link characteristics address, and OPTIONALLY, Layer 3 addresses), link characteristics
(metrics), and OPTIONALLY, flow control information (credits). (metrics), and OPTIONALLY, flow control information (credits).
DLEP assumes that any signal not understood by a receiver MUST result DLEP assumes that any message not understood by a receiver MUST
in an error indication being sent to the originator, and also MUST result in an error indication being sent to the originator, and also
result in termination of the session between the DLEP peers. Any MUST result in termination of the session between the DLEP peers.
DLEP data item not understood by a receiver MUST also result in Any DLEP data item not understood by a receiver MUST also result in
termination of the session. termination of the session.
DLEP assumes that security on the session (e.g., authentication of DLEP assumes that security on the session (e.g., authentication of
session partners, encryption of traffic, or both) is dealt with by session partners, encryption of traffic, or both) is dealt with by
the underlying transport mechanism (e.g., by using a transport such the underlying transport mechanism (e.g., by using a transport such
as TLS [RFC5246]). as TLS [RFC5246]).
This document specifies an implementation of the DLEP signals and This document specifies an implementation of the DLEP messages
data items running over the TCP transport. It is assumed that DLEP running over the TCP transport. It is assumed that DLEP running over
running over other transport mechanisms would be documented other transport mechanisms would be documented separately.
separately.
3. Core Features and Optional Extensions 3. Core Features and Extensions
DLEP has a core set of signals and data items that MUST be processed DLEP has a core set of signals, messages and data items that MUST be
without error by an implementation in order to guarantee parsed without error by an implementation in order to guarantee
interoperability and therefore make the implementation DLEP interoperability and therefore make the implementation DLEP
compliant. This document defines the core set of signals and data compliant. This document defines this set of signals, messages and
items, listing them as 'mandatory'. It should be noted that some data items, listing them as 'core'. It should be noted that some
core signals and data items might not be used during the lifetime of core signals, messages and data items might not be used during the
a single DLEP session, but a compliant implementation MUST support lifetime of a single DLEP session, but a compliant implementation
them. MUST support them.
While this document represents the best efforts of the working group While this document represents the best efforts of the working group
to be functionally complete, it is recognized that extensions to DLEP to be functionally complete, it is recognized that extensions to DLEP
will in all likelihood be necessary as more link types are used. To will in all likelihood be necessary as more link types are used.
support future extension of DLEP, this document describes an
extension negotiation capability to be used during session
initialization via the Extensions Supported data item, documented in
Section 8.7 of this document.
All extensions are considered OPTIONAL. Only the DLEP functionality
listed as 'mandatory' is required by implementation in order to be
DLEP compliant.
This specification defines one extension, Credit windowing, exposed
via the Extensions Supported mechanism that implementations MAY
choose to implement, or to omit.
3.1. Negotiation of Optional Extensions
Optional extensions supported by an implementation MUST be declared If interoperable protocol extensions are required, they MUST be
to potential DLEP peers using the Extensions Supported data item standardized either as an update to this document, or as an
(Section 8.7) during the session initialization sequence. Once both additional stand-alone specification. The requests for IANA-
peers have exchanged initialization signals, an implementation MUST controlled registries in this document contain sufficient Reserved
NOT emit any signal or data item associated with an optional space, in terms of DLEP signals, messages, data items and status
extension that was not specified in the received initialization codes, to accommodate future extensions to the protocol and the data
signal from its peer. transferred.
3.2. Protocol Extensions All extensions are considered OPTIONAL. Extensions may be negotiated
on a per-session basis during session initialization via the
Extensions Supported mechanism. Only the DLEP functionality listed
as 'core' is required by an implementation in order to be DLEP
compliant.
If/when protocol extensions are required, they should be standardized This specification defines one extension, Credit Windowing, that
either as an update to this document, or as an additional stand-alone devices MAY choose to implement.
specification. The requests for IANA-controlled registries in this
document contain sufficient reserved space, both in terms of DLEP
signals and DLEP data items, to accommodate future extensions to the
protocol and the data transferred.
3.3. Experimental Signals and Data Items 3.1. Experiments
This document requests numbering space in both the DLEP signal and This document requests Private Use numbering space in the DLEP
data item registries for experimental items. The intent is to allow signal/message, data item and status code registries for experimental
for experimentation with either (1) new signals, (2) new data items, items. The intent is to allow for experimentation with new signals,
or (3) both new signals and new data items, while still retaining the messages, data items, and/or status codes, while still retaining the
documented DLEP behavior. If a given experiment proves successful, documented DLEP behavior.
it SHOULD be documented as an update to this document, or as a stand-
alone specification.
Use of the experimental signals, data items, or behaviors MUST be Use of the experimental signals, messages, data items, status codes,
announced by inclusion of an Experimental Definition data item or behaviors MUST be announced as Extensions, using extension
(Section 8.8) with a value agreed upon (a priori) between the identifiers from the Private Use space in the Extensions Supported
participating peers. The exact mechanism for a priori communication registry (Table 4), during session initialization with a value agreed
of the experimental definition formats is beyond the scope of this upon (a priori) between the participating peers.
document.
Multiple Experimental Definition data items MAY appear in the Peer Multiple experiments MAY be announced in the Session Initialization
Initialization/Peer Initialization ACK sequence. However, use of messages. However, use of multiple experiments in a single session
multiple experiments in a single peer session could lead to could lead to interoperability issues or unexpected results (e.g.,
interoperability issues or unexpected results (e.g., redefinition of clashes of experimental signals, messages, data items and/or status
experimental signals and/or data items), and is therefore code types), and is therefore discouraged. It is left to
discouraged. It is left to implementations to determine the correct implementations to determine the correct processing path (e.g., a
processing path (e.g., a decision on whether to terminate the peer decision on whether to terminate the session, or to establish a
session, or to establish a precedence of the conflicting definitions) precedence of the conflicting definitions) if such conflicts arise.
if such conflicts arise.
4. Metrics 4. Metrics
DLEP includes the ability for the router and modem to communicate DLEP includes the ability for the router and modem to communicate
metrics that reflect the characteristics (e.g., datarate, latency) of metrics that reflect the characteristics (e.g., datarate, latency) of
the variable-quality link in use. DLEP does NOT specify how a given the variable-quality link in use. DLEP does not specify how a given
metric value is to be calculated, rather, the protocol assumes that metric value is to be calculated, rather, the protocol assumes that
metrics have been calculated with a 'best effort', incorporating all metrics have been calculated with a 'best effort', incorporating all
pertinent data that is available to the modem device. pertinent data that is available to the modem device.
DLEP allows for metrics to be sent within two contexts - metrics for DLEP allows for metrics to be sent within two contexts - metrics for
a specific destination within the network (e.g., a specific router), a specific destination within the network (e.g., a specific router),
and 'modem-wide' (those that apply to all destinations accessed via and per-session (those that apply to all destinations accessed via
the modem). Most metrics can be further subdivided into transmit and the modem). Most metrics can be further subdivided into transmit and
receive metrics. Metrics supplied on DLEP Peer signals are, by receive metrics. In cases where metrics are provided at session
definition, modem-wide; metrics supplied on Destination signals are, level, the receiver MUST propagate the metrics to all entries in its
by definition, used for the specific logical destination only. information base for destinations that are accessed via the
originator.
DLEP modem implementations MUST announce all supported metric items, DLEP modem implementations MUST announce all metric items that will
and provide default values for those metrics, in the Peer be reported during the session, and provide default values for those
Initialization ACK signal (Section 7.4). In order to introduce a new metrics, in the Session Initialization Response message
metric type, DLEP modem implementations MUST terminate the session (Section 8.4). In order to use a metric type that was not included
with the router (via the Peer Terminate signal (Section 7.7)), and in the Session Initialization Response message, modem implementations
allow for session re-establishment. MUST terminate the session with the router (via the Session Terminate
message (Section 8.7)), and establish a new session.
It is left to implementations to choose sensible default values based It is left to implementations to choose sensible default values based
on their specific characteristics. Modems having static (non- on their specific characteristics. Modems having static (non-
changing) link metric characteristics MAY report metrics only once changing) link metric characteristics MAY report metrics only once
for a given destination (or once on a modem-wide basis, if all for a given destination (or once on a modem-wide basis, if all
connections via the modem are of this static nature). connections via the modem are of this static nature).
The approach of allowing for different contexts for metric data A DLEP participant MAY send metrics both in a session context (via
increases both the flexibility and the complexity of using metric the Session Update message) and a specific destination context (via
data. This document details the mechanism whereby the data is Destination Update) at any time. The heuristics for applying
transmitted, however, the specific algorithms (precedence, etc.) for received metrics is left to implementations.
utilizing the dual-context metrics are out of scope and not addressed
by this document.
4.1. Mandatory Metrics 4.1. Mandatory Metrics
As mentioned above, DLEP modem implementations MUST announce all As mentioned above, DLEP modem implementations MUST announce all
supported metric items during session initialization. However, an supported metric items during the Session Initialization state.
implementation MUST include the following list of metrics: However, a modem MUST include the following list of metrics in the
Session Initialization Response message (Section 8.4):
o Maximum Data Rate (Receive) (Section 8.14) o Maximum Data Rate (Receive) (Section 9.12)
o Maximum Data Rate (Transmit) (Section 8.15) o Maximum Data Rate (Transmit) (Section 9.13)
o Current Data Rate (Receive) (Section 8.16) o Current Data Rate (Receive) (Section 9.14)
o Current Data Rate (Transmit) (Section 8.17) o Current Data Rate (Transmit) (Section 9.15)
o Latency (Section 8.18) o Latency (Section 9.16)
5. DLEP Session Flow 5. DLEP Session Flow
For routers supporting DLEP, support of Discovery is optional. All DLEP peers transition through four (4) distinct states during the
Discovery is initiated in the DLEP modem by sending the Peer lifetime of a DLEP session:
Discovery Signal (Section 7.1) to a well-known multicast address.
However, support for receipt and processing of the signal is optional
in the router (see Appendix A for flow diagrams of the discovery
signal). Due to the optional (on the router) support for discovery,
normal session flow is described for both the 'Discovery case', and
the 'Configured case'. Again, for modem implementations of DLEP,
support of Discovery is mandatory; therefore, that is the only case
to be described.
5.1. DLEP Router session flow - Discovery case o Peer Discovery
If the DLEP router implementation is utilizing the optional discovery o Session Initialization
mechanism, then the implementation will initialize a UDP socket,
binding it to an arbitrary port. This UDP socket is used to send the
Peer Discovery signal (Section 7.1) to the DLEP link-local multicast
address and port (TBD). The implementation then waits on receipt of
a Peer Offer signal (Section 7.2), which MAY contain the unicast
address and port for TCP-based communication with a DLEP modem, via
the IPv4 Connection Point data item (Section 8.3) or the IPv6
Connection Point data item (Section 8.4). The Peer Offer signal MAY
contain multiple IP Connection Point data items. If more than one IP
Connection Point data items is in the Peer Offer, router
implementations MAY use their own heuristics to determine the best
address/port combination. If no IP Connection Point data items are
included in the Peer Offer signal, the receiver MUST use the origin
address of the signal as the IP address, and the DLEP well-known port
number (Section 11.7) to establish the TCP connection. At this
point, the router implementation MAY either destroy the UDP socket,
or continue to issue Peer Discovery signals to the link-local
address/port combination. In either case, the TCP session
initialization occurs as in the configured case.
5.2. DLEP Router session flow - Configured case o In-Session
When a DLEP router implementation has the address and port o Session Termination
information for a TCP connection to a modem (obtained either via
configuration or via the discovery process described above), the
router will initialize and bind a TCP socket. This socket is used to
connect to the DLEP modem software. After a successful TCP connect,
the router implementation MUST issue a Peer Initialization signal
(Section 7.3) to the DLEP modem. After sending the Peer
Initialization, the router implementation MUST wait for receipt of a
Peer Initialization ACK signal (Section 7.4) from the modem. Receipt
of the Peer Initialization ACK signal containing a Status data item
(Section 8.2) with value 'Success', indicates that the modem has
received and processed the Peer Initialization, and the session MUST
transition to the 'in session' state. At this point, signals
regarding destinations in the network, and/or Peer Update signals
(Section 7.5), can flow on the DLEP session between modem and router,
and Heartbeat signals can begin to flow, if Heartbeats are used. The
'in session' state is maintained until one of the following
conditions occur:
o The session is explicitly terminated (using Peer Termination), or The Peer Discovery state is OPTIONAL to implement for routers. If it
is used, this state is the initial state. If it is not used, then
one or more preconfigured address/port combinations SHOULD be
provided to the router, and the device starts in the Session
Initialization state.
o The session times out, based on supplied timeout values. Modems MUST support the Peer Discovery state.
5.3. DLEP Modem session flow 5.1. Peer Discovery State
DLEP modem implementations MUST support the discovery mechanism. In the Peer Discovery state, routers send UDP packets containing a
Therefore, the normal flow is as follows: Peer Discovery signal (Section 8.1) to the DLEP well-known multicast
address (Section 12.8) and port number (Section 12.7) then await a
unicast UDP packet containing a Peer Offer signal (Section 8.2) from
a modem. While in the Peer Discovery state, Peer Discovery signals
MUST be sent repeatedly by a router, at regular intervals; every
three (3) seconds is RECOMMENDED.
The implementation will initialize a UDP socket, binding that socket In the Peer Discovery state, the modem waits for incoming Peer
to the DLEP link-local multicast address (TBD) and the DLEP well- Discovery signals on the DLEP well-known multicast address and port.
known port number (also TBD). The implementation will then On receipt of a valid signal, it MUST unicast a Peer Offer signal to
initialize a TCP socket, on a unicast address and port. This socket the source address of the received UDP packet. Peer Offer signals
is used to listen for incoming TCP connection requests. MAY contain the unicast address and port for TCP-based communication
with a modem, via the IPv4 Connection Point data item (Section 9.2)
or the IPv6 Connection Point data item (Section 9.3), on which it is
prepared to accept an incoming TCP connection. The modem then begins
listening for incoming TCP connections, and, having accepted one,
enters the Session Initialization state. Anything other than Peer
Discovery signals received on the UDP socket MUST be silently
dropped.
When the modem implementation receives a Peer Discovery signal Modems SHOULD be prepared to accept a TCP connection from a router
(Section 7.1) on the UDP socket, it responds by issuing a Peer Offer that is not using the Discovery mechanism, i.e. a connection attempt
signal (Section 7.2) to the sender of the Peer Discovery signal. The that occurs without a preceeding Peer Discovery signal. The modem
Peer Offer signal MAY contain the unicast address and port of the MUST accept a TCP connection on only one (1) address/port combination
listening TCP socket, as described above. A DLEP modem per session.
implementation MAY respond with ALL address/port combinations that
have an active TCP listen posted. Anything other than Peer Discovery
signals received on the UDP socket MUST be silently dropped.
When the DLEP modem implementation accepts a connection via TCP, it Routers MUST use one or more of the modem address/port combinations
MUST wait for receipt of a Peer Initialization signal (Section 7.3), from the Peer Offer signal or from a priori configuration to
sent by the router. Upon receipt and successful parsing of a Peer establish a new TCP connection to the modem. If more than one modem
Initialization signal, the modem MUST respond with a Peer address/port combinations is available, router implementations MAY
Initialization ACK signal (Section 7.4). The Peer Initialization ACK use their own heuristics to determine the order in which they are
signal MUST contain metric data items for ALL supported metrics. If tried. If a TCP connection cannot be achieved using any of the
an additional metric is to be introduced, the DLEP session between address/port combinations and the Discovery mechanism is in use, then
router and modem MUST be terminated and restarted, and the new metric the router SHOULD resume issuing Peer Discovery signals. If no IP
described in a Peer Initialization ACK signal. Once the Peer Connection Point data items are included in the Peer Offer signal,
Initialization signal (Section 7.3) and Peer Initialization ACK the router MUST use the origin address of the signal as the IP
signal (Section 7.4) have been exchanged, the session is transitioned address, and the DLEP well-known port number.
to the 'in session' state. As in the router case, when the 'in
session' state is reached, signals regarding destinations in the
network, and/or Peer Update signals (Section 7.5), can flow on the
DLEP session between modem and router, and Heartbeat signals can
begin to flow, if Heartbeats are used. The 'in session' state
persists until the session is explicitly terminated (using Peer
Termination), or it times out (based on timeout values).
5.4. Common Session Flow Once a TCP connection has been established with the modem, the router
begins a new session and enters the Session Initialization state. It
is up to the router implementation if Peer Discovery signals continue
to be sent after the device has transitioned to the Session
Initialization state.
In order to maintain the session between router and modem, periodic 5.2. Session Initialization State
Heartbeat signals (Section 7.14) MAY be exchanged. These signals are
intended to keep the session alive, and to verify bidirectional
connectivity between the two participants. If heartbeat signals are
exchanged, they do not begin until the DLEP peer session has entered
the 'in session' state. Each DLEP peer is responsible for the
creation of heartbeat signals. Receipt of any DLEP signal SHOULD
reset the heartbeat interval timer (i.e., valid DLEP signals take the
place of, and obviate the need for, Heartbeat signals).
DLEP also provides a Peer Update signal (Section 7.5), intended to On entering the Session Initialization state, the router MUST send a
Session Initialization message (Section 8.3) to the modem. The
router MUST then wait for receipt of a Session Initialization
Response message (Section 8.4) from the modem. Receipt of the
Session Initialization Response message containing a Status data item
(Section 9.1) with value 'Success', see Table 3, indicates that the
modem has received and processed the Session Initialization message,
and the router MUST transition to the In-Session state.
On entering the Session Initialization state, the modem MUST wait for
receipt of a Session Initialization message from the router. Upon
receipt and successful parsing of a Session Initialization message,
the modem MUST send a Session Initialization Response message, and
the session MUST transition to the In-Session state.
As mentioned before, DLEP provides an extension negotiation
capability to be used in the Session Initialization state.
Extensions supported by an implementation MUST be declared to
potential DLEP peers using the Extensions Supported data item
(Section 9.6).
Once both peers have exchanged initialization messages, an
implementation MUST NOT emit any message, signal, data item or status
code associated with an extension that was not specified in the
received initialization message from its peer.
If the router receives any message other than a valid Session
Initialization Response, it MUST send a Session Termination message
(Section 8.7) with a relevant status code, e.g. 'Unexpected
Message', see Table 3, and transition to the Session Termination
state.
If the modem receives any message other than Session Initialization,
or it fails to parse the received message, it MUST NOT send any
message, and MUST terminate the TCP connection, then restart at the
Peer Discovery state.
As mentioned before, the Session Initialization Response message MUST
contain metric data items for ALL metrics that will be used during
the session. If an additional metric is to be introduced after the
session has started, the session between router and modem MUST be
terminated and restarted, and the new metric described in the next
Session Initialization Response message.
5.3. In-Session State
In the In-Session state, messages can flow in both directions between
peers, indicating changes to the session state, the arrival or
departure of reachable destinations, or changes of the state of the
links to the destinations.
In order to maintain the In-Session state, periodic Heartbeat
messages (Section 8.14) MAY be exchanged between router and modem.
These messages are intended to keep the session alive, and to verify
bidirectional connectivity between the two participants. Each DLEP
peer is responsible for the creation of heartbeat messages. Receipt
of any valid DLEP message MUST reset the heartbeat interval timer
(i.e., valid DLEP messages take the place of, and obviate the need
for, Heartbeat messages).
DLEP provides a Session Update message (Section 8.5), intended to
communicate some change in status (e.g., a change of layer 3 address communicate some change in status (e.g., a change of layer 3 address
parameters, or a modem-wide link change). parameters, or a modem-wide link change).
In addition to the local (Peer level) signals above, the participants In addition to the session messages, the participants will transmit
will transmit DLEP signals concerning destinations in the network. messages concerning destinations in the network. These messages
These signals trigger creation/maintenance/deletion of destinations trigger creation/maintenance/deletion of destinations in the
in the information base of the recipient. For example, a modem will information base of the recipient. For example, a modem will inform
inform its attached router of the presence of a new destination via its attached router of the presence of a new destination via the
the Destination Up signal (Section 7.9). Receipt of a Destination Up Destination Up message (Section 8.9). Receipt of a Destination Up
causes the router to allocate the necessary resources, creating an causes the router to allocate the necessary resources, creating an
entry in the information base with the specifics (i.e. MAC Address, entry in the information base with the specifics (i.e. MAC Address,
Latency, Data Rate, etc.) of the destination. The loss of a Latency, Data Rate, etc.) of the destination. The loss of a
destination is communicated via the Destination Down signal destination is communicated via the Destination Down message
(Section 7.11), and changes in status to the destination (e.g., (Section 8.11), and changes in status to the destination (e.g.,
varying link quality, or addressing changes) are communicated via the varying link quality, or addressing changes) are communicated via the
Destination Update signal (Section 7.13). The information on a given Destination Update message (Section 8.13). The information on a
destination will persist in the router's information base until (1) a given destination will persist in the router's information base until
Destination Down signal is received, indicating that the modem has (1) a Destination Down message is received, indicating that the modem
lost contact with the remote node, or (2) the router/modem session has lost contact with the remote node, or (2) the router/modem
terminates, indicating that the router has lost contact with its own transitions to the Session Termination state.
local modem.
Metrics can be expressed within the context of a specific destination
via the Destination Update signal, or on a modem-wide basis via the
Peer Update signal. In cases where metrics are provided at peer
level, the receiver MUST propagate the metrics to all entries in its
information base for destinations that are accessed via the
originator. A DLEP participant MAY send metrics both in a router/
modem session context (via the Peer Update signal) and a specific
destination context (via Destination Update) at any time. The
heuristics for applying received metrics is left to implementations.
In addition to receiving metrics about the link, DLEP provides a In addition to receiving metrics about the link, DLEP provides a
signal allowing a router to request a different datarate, or latency, message allowing a router to request a different datarate, or
from the modem. This signal is referred to as the Link latency, from the modem. This message is referred to as the Link
Characteristics Request signal (Section 7.15), and gives the router Characteristics Request message (Section 8.15), and gives the router
the ability to deal with requisite increases (or decreases) of the ability to deal with requisite increases (or decreases) of
allocated datarate/latency in demand-based schemes in a more allocated datarate/latency in demand-based schemes in a more
deterministic manner. deterministic manner.
6. DLEP Signal Structure and Processing The In-Session state is maintained until one of the following
conditions occur:
Communication between DLEP peers consists of a bidirectional stream o The implementation terminates the session by sending a Session
of signals (messages), each signal consisting of a signal header and Termination message (Section 8.7)), or
an unordered list of data items. Signal headers consist of Type and
Length information, while data items are encoded as TLV (Type-Length-
Value) structures. In this document, the data items following the
signal header are described as being 'contained in' the signal.
All integer values structures MUST be in network byte-order. o The DLEP peer terminates the session, indicated by receiving a
Session termination message.
The implementation MUST then transition to the Session Termination
state.
5.4. Session Termination State
When a DLEP implementation enters the Session Termination state after
sending a Session Termination message (Section 8.7) as the result of
an invalid message or error, it MUST wait for a Session Termination
Response message (Section 8.8) from its peer. If Heartbeat messages
(Section 8.14) are in use, senders SHOULD allow four (4) heartbeat
intervals to expire before assuming that the peer is unresponsive,
and continuing with session termination. If Heartbeat messages are
not in use, then if is RECOMMENDED that an interval of eight (8)
seconds be used.
When a DLEP implementation enters the Session Termination state
having received a Session Termination message from its peer, it MUST
immediately send a Session Termination Response.
The sender and receiver of a Session Termination message MUST release
all resources allocated for the session, and MUST eliminate all
destinations in the information base accessible via the peer
represented by the session. No Destination Down messages
(Section 8.11) are sent.
Any messages received after either sending or receiving a Session
Termination message MUST be silently ignored.
Once Session Termination messages have been exchanged, or timed out,
the device MUST terminate the TCP connection to the peer, and return
to the relevant initial state.
6. DLEP Signal and Message Processing
Most messages in DLEP are members of a request/response pair, e.g.
Destination Up message (Section 8.9), and Destination Up Response
message (Section 8.10). These pairs of messages define an implicit
transaction model for both session messages and destination messages.
As mentioned before, session message pairs control the flow of the
session through the various states, e.g. an implementation MUST NOT
leave the Session Initialization state until a Session Initialization
message (Section 8.3) and Session Initialization Response message
(Section 8.4) have been exchanged.
Destination message pairs describe the arrival and departure of
logical destinations, and control the flow of information about the
destinations in the several ways.
Prior to the exchange of a pair of Destination Up and Destination Up
Response messages, no messages concerning the logical destination
identified by the MAC Address data item (Section 9.7) may be sent.
An implementation receiving a message with such an unannounced
destination MUST terminate the session by issuing a Session
Termination message (Section 8.7) with a status code of 'Invalid
Destination', see Table 3, and transition to the Session Termination
state.
The receiver of a Destination Up message MAY decline further messages
concerning a given destination by sending a Destination Up Response
with a status code of 'Not Interested', see Table 3. Receivers of
such responses MUST NOT send further messages concerning that
destination to the peer.
After exchanging a pair of Destination Down (Section 8.11) and
Destination Down Response (Section 8.12) messages, no messages
concerning the logical destination identified by the MAC Address data
item may be a sent without a previously sending a new Destination Up
message. An implementation receiving a message about a down
destination MUST terminate the session by issuing a Session
Termination message with a status code of 'Invalid Destination' and
transition to the Session Termination state.
7. DLEP Signal and Message Structure
DLEP defines two protocol units used in two different ways: Signals
and Messages. Signals are only used in the Discovery mechanism and
are carried in UDP datagrams. Messages are used bi-directionally
over a TCP connection between two peers, in the Session
Initialization, In-Session and Session Termination states.
Both signals and messages consist of a header followed by an
unordered list of data items. Headers consist of Type and Length
information, while data items are encoded as TLV (Type-Length-Value)
structures. In this document, the data items following a signal or
message header are described as being 'contained in' the signal or
message.
There is no restriction on the order of data items following a There is no restriction on the order of data items following a
signal, and the multiplicity of duplicate data items is defined by header, and the multiplicity of duplicate data items is defined by
the definition of the signal declared by the type in the signal the definition of the signal or message declared by the type in the
header. header.
If an unrecognized, or unexpected signal is received, or a received All integers in header fields and values MUST be in network byte-
signal contains unrecognized, invalid, or disallowed duplicate data order.
items, the receiving peer MUST terminate the session by issuing a
Peer Termination signal (Section 7.7) with a Status data item
(Section 8.2) containing the most relevant status code, and then
close the TCP connection.
6.1. DLEP Signal Header 7.1. DLEP Signal Header
The DLEP signal header contains the following fields: The DLEP signal header contains the following fields:
0 1 2 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signal Type | Length | | 'D' | 'L' | 'E' | 'P' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signal Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: DLEP Signal Header Figure 3: DLEP Signal Header
Signal Type: An 8-bit unsigned integer containing one of the DLEP "DLEP": Every signal MUST start with the characters: U+44, U+4C,
Signal Type values defined in this document. U+45, U+50.
Length: The length, expressed as a 16-bit unsigned integer, of all Signal Type: An 16-bit unsigned integer containing one of the DLEP
of the DLEP data items associated with this signal. This length Signal/Message Type values defined in this document.
does not include the length of the header itself
The DLEP Signal Header is immediately followed by one or more DLEP Length: The length in octets, expressed as a 16-bit unsigned
integer, of all of the DLEP data items associated with this
signal. This length SHALL NOT include the length of the header
itself.
The DLEP signal header is immediately followed by one or more DLEP
data items, encoded in TLVs, as defined in this document. data items, encoded in TLVs, as defined in this document.
6.2. DLEP Generic Data Item If an unrecognized, or unexpected signal is received, or a received
signal contains unrecognized, invalid, or disallowed duplicate data
items, the receiving peer MUST ignore the signal.
7.2. DLEP Message Header
The DLEP message header contains the following fields:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: DLEP Message Header
Message Type: An 16-bit unsigned integer containing one of the DLEP
Signal/Message Type values defined in this document.
Length: The length in octets, expressed as a 16-bit unsigned
integer, of all of the DLEP data items associated with this
message. This length SHALL NOT include the length of the header
itself.
The DLEP message header is immediately followed by one or more DLEP
data items, encoded in TLVs, as defined in this document.
If an unrecognized, or unexpected message is received, or a received
message contains unrecognized, invalid, or disallowed duplicate data
items, the receiving peer MUST issue a Session Termination message
(Section 8.7) with a Status data item (Section 9.1) containing the
most relevant status code, and transition to the Session Termination
state.
7.3. DLEP Generic Data Item
All DLEP data items contain the following fields: All DLEP data items contain the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Value... | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: DLEP Generic Data Item Figure 5: DLEP Generic Data Item
Data Item Type: An 8-bit unsigned integer field specifying the data Data Item Type: An 16-bit unsigned integer field specifying the type
item being sent. of data item being sent.
Length: The length, expressed as an 8-bit unsigned integer, of the Length: The length in octets, expressed as an 16-bit unsigned
value field of the data item. integer, of the value field of the data item. This length SHALL
NOT include the length of the header itself.
Value: A field of length <Length> which contains data specific to a Value: A field of <Length> octets, which contains data specific to a
particular data item. particular data item.
7. DLEP Signals 8. DLEP Signals and Messages
As mentioned above, all DLEP signals begin with the DLEP signal As mentioned above, all DLEP signals begin with the DLEP signal
header structure. Therefore, in the following descriptions of header, and all DLEP messages begin with the DLEP message header.
specific signals, this header structure is assumed, and will not be Therefore, in the following descriptions of specific signals and
replicated. messages, this header is assumed, and will not be replicated.
Following is the set of MANDATORY signals that must be recognized by Following is the set of core signals and messages that MUST be
a DLEP compliant implementation. As mentioned before, not all recognized by a DLEP compliant implementation. As mentioned before,
signals may be used during a session, but an implementation MUST not all messages may be used during a session, but an implementation
correctly process these signals when received. MUST correctly process these messages when received.
The mandatory DLEP signals are: The core DLEP signals and messages are:
+--------+--------------------+----------------------+--------------+ +-------------+-----------------------------------------------------+
| Signal | Description | Mnemonic | Section | | Type Code | Description |
+--------+--------------------+----------------------+--------------+ +-------------+-----------------------------------------------------+
| TBD | Peer Discovery | DLEP_PEER_DISCOVERY | Section 7.1 | | 0 | Reserved |
| TBD | Peer Offer | DLEP_PEER_OFFER | Section 7.2 | | 1 | Peer Discovery signal (Section 8.1) |
| TBD | Peer | DLEP_PEER_INIT | Section 7.3 | | 2 | Peer Offer signal (Section 8.2) |
| | Initialization | | | | 3 | Session Initialization message (Section 8.3) |
| TBD | Peer | DLEP_PEER_INIT_ACK | Section 7.4 | | 4 | Session Initialization Response message (Section |
| | Initialization ACK | | | | | 8.4) |
| TBD | Peer Update | DLEP_PEER_UPDATE | Section 7.5 | | 5 | Session Update message (Section 8.5) |
| TBD | Peer Update ACK | DLEP_PEER_UPDATE_ACK | Section 7.6 | | 6 | Session Update Response message (Section 8.6) |
| TBD | Peer Termination | DLEP_PEER_TERM | Section 7.7 | | 7 | Session Termination message (Section 8.7) |
| TBD | Peer Termination | DLEP_PEER_TERM_ACK | Section 7.8 | | 8 | Session Termination Response message (Section 8.8) |
| | ACK | | | | 9 | Destination Up message (Section 8.9) |
| TBD | Destination Up | DLEP_DEST_UP | Section 7.9 | | 10 | Destination Up Response message (Section 8.10) |
| TBD | Destination Up ACK | DLEP_DEST_UP_ACK | Section 7.10 | | 11 | Destination Down message (Section 8.11) |
| TBD | Destination Down | DLEP_DEST_DOWN | Section 7.11 | | 12 | Destination Down Response message (Section 8.12) |
| TBD | Destination Down | DLEP_DEST_DOWN_ACK | Section 7.12 | | 13 | Destination Update message (Section 8.13) |
| | ACK | | | | 14 | Heartbeat message (Section 8.14) |
| TBD | Destination Update | DLEP_DEST_UPDATE | Section 7.13 | | 15 | Link Characteristics Request message (Section 8.15) |
| TBD | Heartbeat | DLEP_PEER_HEARTBEAT | Section 7.14 | | 16 | Link Characteristics Response message (Section |
| TBD | Link | DLEP_LINK_CHAR_REQ | Section 7.15 | | | 8.16) |
| | Characteristics | | | | 17-65519 | Reserved for future extensions |
| | Request | | | | 65520-65534 | Private Use. Available for experiments |
| TBD | Link | DLEP_LINK_CHAR_ACK | Section 7.16 | | 65535 | Reserved |
| | Characteristics | | | +-------------+-----------------------------------------------------+
| | ACK | | |
+--------+--------------------+----------------------+--------------+
Table 1: DLEP Signal Values Table 1: DLEP Signal/Message types
7.1. Peer Discovery Signal 8.1. Peer Discovery Signal
A Peer Discovery signal SHOULD be sent by a router to discover DLEP A Peer Discovery signal SHOULD be sent by a router to discover DLEP
modems in the network. The Peer Offer signal (Section 7.2) is modems in the network. The Peer Offer signal (Section 8.2) is
required to complete the discovery process. Implementations MAY required to complete the discovery process. Implementations MAY
implement their own retry heuristics in cases where it is determined implement their own retry heuristics in cases where it is determined
the Peer Discovery signal has timed out. the Peer Discovery signal has timed out.
To construct a Peer Discovery signal, the Signal Type value in the To construct a Peer Discovery signal, the Signal Type value in the
signal header is set to DLEP_PEER_DISCOVERY in Table 1. signal header is set to 1, from Table 1.
The Peer Discovery signal MUST contain the following data item:
o DLEP Version (Section 8.1)
The Peer Discovery signal MAY contain the following data item: The Peer Discovery signal MAY contain the following data item:
o Peer Type (Section 8.5) o Peer Type (Section 9.4)
7.2. Peer Offer Signal 8.2. Peer Offer Signal
A Peer Offer signal MUST be sent by a DLEP modem in response to a A Peer Offer signal MUST be sent by a DLEP modem in response to a
valid Peer Discovery signal (Section 7.1). valid Peer Discovery signal (Section 8.1).
The Peer Offer signal MUST be sent to the unicast address of the The Peer Offer signal MUST be sent to the unicast address of the
originator of the Peer Discovery signal. originator of the Peer Discovery signal.
To construct a Peer Offer signal, the Signal Type value in the signal To construct a Peer Offer signal, the Signal Type value in the signal
header is set to DLEP_PEER_OFFER in Table 1. header is set to 2, from Table 1.
The Peer Offer signal MUST contain the following data item:
o DLEP Version (Section 8.1)
The Peer Offer signal MAY contain the following data item: The Peer Offer signal MAY contain the following data item:
o Peer Type (Section 8.5) o Peer Type (Section 9.4)
The Peer Offer signal MAY contain one or more of any of the following The Peer Offer signal MAY contain one or more of any of the following
data items, with different values: data items, with different values:
o IPv4 Connection Point (Section 8.3) o IPv4 Connection Point (Section 9.2)
o IPv6 Connection Point (Section 8.4) o IPv6 Connection Point (Section 9.3)
The IP Connection Point data items indicate the unicast address the The IP Connection Point data items indicate the unicast address the
receiver of Peer Offer MUST use when connecting the DLEP TCP session. receiver of Peer Offer MUST use when connecting the DLEP TCP session.
If multiple IP Connection Point data items are present in the Peer If multiple IP Connection Point data items are present in the Peer
Offer signal, implementations MAY use their own heuristics to select Offer signal, implementations MAY use their own heuristics to select
the address to connect to. If no IP Connection Point data items are the address to connect to. If no IP Connection Point data items are
included in the Peer Offer signal, the receiver MUST use the origin included in the Peer Offer signal, the receiver MUST use the origin
address of the signal as the IP address, and the DLEP well-known port address of the signal as the IP address, and the DLEP well-known port
number (Section 11.7) to establish the TCP connection. number (Section 12.7) to establish the TCP connection.
7.3. Peer Initialization Signal 8.3. Session Initialization Message
A Peer Initialization signal MUST be sent by a router as the first A Session Initialization message MUST be sent by a router as the
signal of the DLEP TCP session. It is sent by the router after a TCP first message of the DLEP TCP session. It is sent by the router
connect to an address/port combination that was obtained either via after a TCP connect to an address/port combination that was obtained
receipt of a Peer Offer, or from a priori configuration. either via receipt of a Peer Offer, or from a priori configuration.
If any optional extensions are supported by the implementation, they If any optional extensions are supported by the implementation, they
MUST be enumerated in the Extensions Supported data item. If an MUST be enumerated in the Extensions Supported data item. If an
Extensions Supported data item does not exist in a Peer Extensions Supported data item does not exist in a Session
Initialization signal, the receiver of the signal MUST conclude that Initialization message, the receiver of the message MUST conclude
there is NO support for extensions in the sender. that there is no support for extensions in the sender.
If any experimental signals or data items are used by the
implementation, they MUST be enumerated in one or more Experimental
Definition data items. If there are no Experimental Definition data
items in a Peer Initialization signal, the receiver of the signal
MUST conclude that no experimental definitions are in use by the
sender.
Implementations supporting the Heartbeat Interval (Section 8.6) Implementations supporting the Heartbeat Interval (Section 9.5)
should understand that heartbeats are not fully established until should understand that heartbeats are not fully established until
receipt of Peer Initialization ACK Signal (Section 7.4), and should receipt of Session Initialization Response message (Section 8.4), and
therefore implement their own timeout and retry heuristics for this should therefore implement their own timeout and retry heuristics for
signal. this message.
To construct a Peer Initialization signal, the Signal Type value in To construct a Session Initialization message, the Message Type value
the signal header is set to DLEP_PEER_INIT in Table 1. in the message header is set to 3, from Table 1.
The Peer Initialization signal MUST contain one of each of the The Session Initialization message MUST contain one of each of the
following data items: following data items:
o DLEP Version (Section 8.1) o Heartbeat Interval (Section 9.5)
o Heartbeat Interval (Section 8.6)
The Peer Initialization signal MAY contain one of each of the The Session Initialization message MAY contain one of each of the
following data items: following data items:
o Peer Type (Section 8.5) o Peer Type (Section 9.4)
o Extensions Supported (Section 8.7)
The Peer Initialization signal MAY contain one or more of any of the
following data items, with different values:
o Experimental Definition (Section 8.8) o Extensions Supported (Section 9.6)
A Peer Initialization signal MUST be acknowledged by the receiver A Session Initialization message MUST be acknowledged by the receiver
issuing a Peer Initialization ACK signal (Section 7.4). issuing a Session Initialization Response message (Section 8.4).
7.4. Peer Initialization ACK Signal 8.4. Session Initialization Response Message
A Peer Initialization ACK signal MUST be sent in response to a A Session Initialization Response message MUST be sent in response to
received Peer Initialization signal (Section 7.3). The Peer a received Session Initialization message (Section 8.3). The Session
Initialization ACK signal completes the DLEP session establishment; Initialization Response message completes the DLEP session
the sender of the signal should transition to an 'in-session' state establishment; the sender of the message should transition to the In-
when the signal is sent, and the receiver should transition to the Session state when the message is sent, and the receiver should
'in-session' state upon receipt (and successful parsing) of an transition to the In-Session state upon receipt (and successful
acceptable Peer Initialization ACK signal. parsing) of an acceptable Session Initialization Response message.
All supported metric data items MUST be included in the Peer All supported metric data items MUST be included in the Session
Initialization ACK signal, with default values to be used on a Initialization Response message, with default values to be used on a
'modem-wide' basis. This can be viewed as the modem 'declaring' all 'modem-wide' basis. This can be viewed as the modem 'declaring' all
supported metrics at DLEP session initialization. Receipt of any supported metrics at DLEP session initialization. Receipt of any
DLEP signal containing a metric data item NOT included in the Peer DLEP message containing a metric data item not included in the
Initialization ACK signal MUST be treated as an error, resulting in Session Initialization Response message MUST be treated as an error,
the termination of the DLEP session between router and modem. resulting in the termination of the DLEP session between router and
modem.
If any optional extensions are supported by the modem, they MUST be If any optional extensions are supported by the modem, they MUST be
enumerated in the Extensions Supported data item. If an Extensions enumerated in the Extensions Supported data item. If an Extensions
Supported data item does NOT exist in a Peer Initialization ACK Supported data item does not exist in a Session Initialization
signal, the receiver of the signal MUST conclude that there is NO Response message, the receiver of the message MUST conclude that
support for extensions in the sender. there is no support for extensions in the sender.
If any experimental signals or data items are used by the
implementation, they MUST be enumerated in one or more Experimental
Definition data items. If there are no Experimental Definition data
items in a Peer Initialization ACK signal, the receiver of the signal
MUST conclude that NO experimental definitions are in use by the
sender.
After the Peer Initialization/Peer Initialization ACK signals have After the Session Initialization/Session Initialization Response
been successfully exchanged, implementations MUST only use extensions messages have been successfully exchanged, implementations MUST only
and experimental definitions that are supported by BOTH peers. use extensions that are supported by BOTH peers.
To construct a Peer Initialization ACK signal, the Signal Type value To construct a Session Initialization Response message, the Message
in the signal header is set to DLEP_PEER_INIT_ACK in Table 1. Type value in the message header is set to 4, from Table 1.
The Peer Initialization ACK signal MUST contain one of each of the The Session Initialization Response message MUST contain one of each
following data items: of the following data items:
o DLEP Version (Section 8.1) o Heartbeat Interval (Section 9.5)
o Heartbeat Interval (Section 8.6) o Maximum Data Rate (Receive) (Section 9.12)
o Maximum Data Rate (Receive) (Section 8.14) o Maximum Data Rate (Transmit) (Section 9.13)
o Maximum Data Rate (Transmit) (Section 8.15) o Current Data Rate (Receive) (Section 9.14)
o Current Data Rate (Receive) (Section 8.16) o Current Data Rate (Transmit) (Section 9.15)
o Current Data Rate (Transmit) (Section 8.17) o Latency (Section 9.16)
o Latency (Section 8.18) The Session Initialization Response message MUST contain one of each
The Peer Initialization ACK signal MUST contain one of each of the of the following data items, if the data item will be used during the
following data items, if the data item will be used during the
lifetime of the session: lifetime of the session:
o Resources (Receive) (Section 8.19) o Resources (Receive) (Section 9.17)
o Resources (Transmit) (Section 8.20)
o Relative Link Quality (Receive) (Section 8.21) o Resources (Transmit) (Section 9.18)
o Relative Link Quality (Transmit) (Section 8.22) o Relative Link Quality (Receive) (Section 9.19)
The Peer Initialization ACK signal MAY contain one of each of the o Relative Link Quality (Transmit) (Section 9.20)
following data items:
o Status (Section 8.2) The Session Initialization Response message MAY contain one of each
of the following data items:
o Peer Type (Section 8.5) o Status (Section 9.1)
o Extensions Supported (Section 8.7) o Peer Type (Section 9.4)
The Peer Initialization ACK signal MAY contain one or more of any of o Extensions Supported (Section 9.6)
the following data items, with different values:
o Experimental Definition (Section 8.8) A receiver of a Session Initialization Response message without a
Status data item MUST behave as if a Status data item with code
'Success' had been received.
7.5. Peer Update Signal 8.5. Session Update Message
A Peer Update signal MAY be sent by a DLEP peer to indicate local A Session Update message MAY be sent by a DLEP peer to indicate local
Layer 3 address changes, or metric changes on a modem-wide basis. Layer 3 address changes, or metric changes on a modem-wide basis.
For example, addition of an IPv4 address to the router MAY prompt a For example, addition of an IPv4 address to the router MAY prompt a
Peer Update signal to its attached DLEP modems. Also, for example, a Session Update message to its attached DLEP modems. Also, for
modem that changes its Maximum Data Rate (Receive) for all example, a modem that changes its Maximum Data Rate (Receive) for all
destinations MAY reflect that change via a Peer Update signal to its destinations MAY reflect that change via a Session Update message to
attached router(s). its attached router(s).
Concerning Layer 3 addresses, if the modem is capable of Concerning Layer 3 addresses, if the modem is capable of
understanding and forwarding this information (via proprietary understanding and forwarding this information (via proprietary
mechanisms), the address update would prompt any remote DLEP modems mechanisms), the address update would prompt any remote DLEP modems
(DLEP-enabled modems in a remote node) to issue a Destination Update (DLEP-enabled modems in a remote node) to issue a Destination Update
signal (Section 7.13) to their local routers with the new (or message (Section 8.13) to their local routers with the new (or
deleted) addresses. Modems that do not track Layer 3 addresses deleted) addresses. Modems that do not track Layer 3 addresses
SHOULD silently parse and ignore Layer 3 data items. The Peer Update SHOULD silently parse and ignore Layer 3 data items. The Session
Signal MUST be acknowledged with a Peer Update ACK signal Update message MUST be acknowledged with a Session Update Response
(Section 7.6). message (Section 8.6).
If metrics are supplied with the Peer Update signal (e.g., Maximum If metrics are supplied with the Session Update message (e.g.,
Data Rate), these metrics are considered to be modem-wide, and Maximum Data Rate), these metrics are considered to be modem-wide,
therefore MUST be applied to all destinations in the information base and therefore MUST be applied to all destinations in the information
associated with the router/modem session. base associated with the router/modem session.
Supporting implementations are free to employ heuristics to Supporting implementations are free to employ heuristics to
retransmit Peer Update signals. The sending of Peer Update signals retransmit Session Update messages. The sending of Session Update
for Layer 3 address changes SHOULD cease when either participant messages for Layer 3 address changes SHOULD cease when either
(router or modem) determines that the other implementation does NOT participant (router or modem) determines that the other
support Layer 3 address tracking. implementation does not support Layer 3 address tracking.
To construct a Peer Update signal, the Signal Type value in the
signal header is set to DLEP_PEER_UPDATE in Table 1.
The Peer Update signal MAY contain one of each of the following data
items:
o Maximum Data Rate (Receive) (Section 8.14)
o Maximum Data Rate (Transmit) (Section 8.15) To construct a Session Update message, the Message Type value in the
message header is set to 5, from Table 1.
o Current Data Rate (Receive) (Section 8.16) The Session Update message MAY contain one of each of the following
data items:
o Current Data Rate (Transmit) (Section 8.17) o Maximum Data Rate (Receive) (Section 9.12)
o Latency (Section 8.18) o Maximum Data Rate (Transmit) (Section 9.13)
o Resources (Receive) (Section 8.19) o Current Data Rate (Receive) (Section 9.14)
o Resources (Transmit) (Section 8.20) o Current Data Rate (Transmit) (Section 9.15)
o Relative Link Quality (Receive) (Section 8.21) o Latency (Section 9.16)
o Relative Link Quality (Transmit) (Section 8.22) o Resources (Receive) (Section 9.17)
o Resources (Transmit) (Section 9.18)
The Peer Update signal MAY contain one or more of the following data o Relative Link Quality (Receive) (Section 9.19)
items, with different values:
o IPv4 Address (Section 8.10) o Relative Link Quality (Transmit) (Section 9.20)
o IPv6 Address (Section 8.11) The Session Update message MAY contain one or more of the following
data items, with different values:
A Peer Update signal MUST be acknowledged by the receiver issuing a o IPv4 Address (Section 9.8)
Peer Update ACK signal (Section 7.6).
7.6. Peer Update ACK Signal o IPv6 Address (Section 9.9)
A Peer Update ACK signal MUST be sent by implementations to indicate A Session Update message MUST be acknowledged by the receiver issuing
whether a Peer Update signal (Section 7.5) was successfully received. a Session Update Response message (Section 8.6).
To construct a Peer Update ACK signal, the Signal Type value in the 8.6. Session Update Response Message
signal header is set to DLEP_PEER_UPDATE_ACK in Table 1.
The Peer Update ACK signal MAY contain one of each of the following A Session Update Response message MUST be sent by implementations to
data items: indicate whether a Session Update message (Section 8.5) was
successfully received.
o Status (Section 8.2) To construct a Session Update Response message, the Message Type
value in the message header is set to 6, from Table 1.
A receiver of a Peer Update ACK signal without a Status data item The Session Update Response message MAY contain one of each of the
MUST behave as if a Status data item with code 'Success' had been following data items:
received.
7.7. Peer Termination Signal o Status (Section 9.1)
A Peer Termination signal MUST be sent by a DLEP participant when the A receiver of a Session Update Response message without a Status data
router/modem session needs to be terminated. Implementations item MUST behave as if a Status data item with code 'Success' had
receiving a Peer Termination signal MUST send a Peer Termination ACK been received.
signal (Section 7.8) to confirm the termination process.
The receiver of a Peer Termination signal MUST release all resources 8.7. Session Termination Message
allocated for the router/modem session, and MUST eliminate all
destinations in the information base accessible via the router/modem
pair represented by the session. Router and modem state machines are
returned to the 'discovery' state. No Destination Down signals
(Section 7.11) are sent.
The sender of a Peer Termination signal is free to define its A Session Termination message MUST be sent by a DLEP participant when
heuristics in event of a timeout. It may resend the Peer Termination the router/modem session needs to be terminated.
or free resources and return to the 'discovery' state.
To construct a Peer Termination signal, the Signal Type value in the To construct a Session Termination message, the Message Type value in
signal header is set to DLEP_PEER_TERM in Table 1. the message header is set to 7, from Table 1.
The Peer Termination signal MAY contain one of each of the following The Session Termination message MAY contain one of each of the
data items: following data items:
o Status (Section 8.2) o Status (Section 9.1)
A receiver of a Session Termination message without a Status data
item MUST behave as if a Status of 'Unknown reason for Session
Termination' has been received.
A receiver of a Peer Termination signal without a Status data item A Session Termination message MUST be acknowledged by the receiver
MUST behave as if a Status of 'Unknown reason for Peer Termination' issuing a Session Termination Response message (Section 8.8).
has been received.
A Peer Termination signal MUST be acknowledged by the receiver 8.8. Session Termination Response Message
issuing a Peer Termination ACK signal (Section 7.8).
7.8. Peer Termination ACK Signal A Session Termination Response message MUST be sent by a DLEP peer in
response to a received Session Termination message (Section 8.7).
A Peer Termination ACK signal MUST be sent by a DLEP peer in response Receipt of a Session Termination Response message completes the
to a received Peer Termination signal (Section 7.7). Receipt of a teardown of the router/modem session.
Peer Termination ACK signal completes the teardown of the router/
modem session.
To construct a Peer Termination ACK signal, the Signal Type value in To construct a Session Termination Response message, the Message Type
the signal header is set to DLEP_PEER_TERM_ACK in Table 1. value in the message header is set to 8, from Table 1.
The Peer Termination ACK signal MAY contain one of each of the The Session Termination Response message MAY contain one of each of
following data items: the following data items:
o Status (Section 8.2) o Status (Section 9.1)
A receiver of a Peer Termination ACK signal without a Status data A receiver of a Session Termination Response message without a Status
item MUST behave as if a Status data item with status code 'Success', data item MUST behave as if a Status data item with status code
implying graceful termination, had been received. 'Success', implying graceful termination, had been received.
7.9. Destination Up Signal 8.9. Destination Up Message
A Destination Up signal can be sent either by the modem, to indicate A Destination Up message can be sent either by the modem, to indicate
that a new remote node has been detected, or by the router, to that a new remote node has been detected, or by the router, to
indicate the presence of a new logical destination (e.g., a Multicast indicate the presence of a new logical destination (e.g., a Multicast
group) in the network. group) in the network.
A Destination Up signal MUST be acknowledged by the receiver issuing A Destination Up message MUST be acknowledged by the receiver issuing
a Destination Up ACK signal (Section 7.10). The sender of the a Destination Up Response message (Section 8.10). The sender of the
Destination Up signal is free to define its retry heuristics in event Destination Up message is free to define its retry heuristics in
of a timeout. When a Destination Up signal is received and event of a timeout. When a Destination Up message is received and
successfully processed, the receiver should add knowledge of the new successfully processed, the receiver should add knowledge of the new
destination to its information base, indicating that the destination destination to its information base, indicating that the destination
is accessible via the modem/router pair. is accessible via the modem/router pair.
To construct a Destination Up signal, the Signal Type value in the To construct a Destination Up message, the Message Type value in the
signal header is set to DLEP_DEST_UP in Table 1. message header is set to 9, from Table 1.
The Destination Up signal MUST contain one of each of the following The Destination Up message MUST contain one of each of the following
data items: data items:
o MAC Address (Section 8.9) o MAC Address (Section 9.7)
The Destination Up signal MAY contain one of each of the following The Destination Up message MAY contain one of each of the following
data items: data items:
o Maximum Data Rate (Receive) (Section 8.14) o Maximum Data Rate (Receive) (Section 9.12)
o Maximum Data Rate (Transmit) (Section 8.15) o Maximum Data Rate (Transmit) (Section 9.13)
o Current Data Rate (Receive) (Section 8.16)
o Current Data Rate (Transmit) (Section 8.17) o Current Data Rate (Receive) (Section 9.14)
o Latency (Section 8.18) o Current Data Rate (Transmit) (Section 9.15)
o Resources (Receive) (Section 8.19) o Latency (Section 9.16)
o Resources (Transmit) (Section 8.20) o Resources (Receive) (Section 9.17)
o Relative Link Quality (Receive) (Section 8.21) o Resources (Transmit) (Section 9.18)
o Relative Link Quality (Transmit) (Section 8.22) o Relative Link Quality (Receive) (Section 9.19)
The Destination Up signal MAY contain one or more of the following o Relative Link Quality (Transmit) (Section 9.20)
The Destination Up message MAY contain one or more of the following
data items, with different values: data items, with different values:
o IPv4 Address (Section 8.10) o IPv4 Address (Section 9.8)
o IPv6 Address (Section 8.11) o IPv6 Address (Section 9.9)
o IPv4 Attached Subnet (Section 8.12) o IPv4 Attached Subnet (Section 9.10)
o IPv6 Attached Subnet (Section 8.13) o IPv6 Attached Subnet (Section 9.11)
If the sender has IPv4 and/or IPv6 address information for a If the sender has IPv4 and/or IPv6 address information for a
destination it SHOULD include the relevant data items in the destination it SHOULD include the relevant data items in the
Destination Up signal, reducing the need for the receiver to probe Destination Up message, reducing the need for the receiver to probe
for any address. for any address.
7.10. Destination Up ACK Signal 8.10. Destination Up Response Message
A DLEP participant MUST send a Destination Up ACK signal to indicate A DLEP participant MUST send a Destination Up Response message to
whether a Destination Up signal (Section 7.9) was successfully indicate whether a Destination Up message (Section 8.9) was
processed. successfully processed.
To construct a Destination Up ACK signal, the Signal Type value in To construct a Destination Up Response message, the Message Type
the signal header is set to DLEP_DEST_UP_ACK in Table 1. value in the message header is set to 10, from Table 1.
The Destination Up ACK signal MUST contain one of each of the The Destination Up Response message MUST contain one of each of the
following data items: following data items:
o MAC Address (Section 8.9) o MAC Address (Section 9.7)
The Destination Up ACK signal MAY contain one of each of the The Destination Up Response message MAY contain one of each of the
following data items: following data items:
o Status (Section 8.2) o Status (Section 9.1)
A receiver of a Destination Up ACK signal without a Status data item
MUST behave as if a Status data item with status code 'Success' had
been received. Implementations are free to define retry heuristics
when receiving a Destination Up ACK signal indicating an error.
7.11. Destination Down Signal A receiver of a Destination Up Response message without a Status data
item MUST behave as if a Status data item with status code 'Success'
had been received.
A DLEP peer MUST send a Destination Down signal to report when a 8.11. Destination Down Message
A DLEP peer MUST send a Destination Down message to report when a
destination (a remote node or a multicast group) is no longer destination (a remote node or a multicast group) is no longer
reachable. A Destination Down ACK signal (Section 7.12) MUST be sent reachable. A Destination Down Response message (Section 8.12) MUST
by the recipient of a Destination Down signal to confirm that the be sent by the recipient of a Destination Down message to confirm
relevant data has been removed from the information base. The sender that the relevant data has been removed from the information base.
of the Destination Down signal is free to define its retry heuristics The sender of the Destination Down message is free to define its
in event of a timeout. retry heuristics in event of a timeout.
To construct a Destination Down signal, the Signal Type value in the To construct a Destination Down message, the Message Type value in
signal header is set to DLEP_DEST_DOWN in Table 1. the message header is set to 11, from Table 1.
The Destination Down signal MUST contain one of each of the following The Destination Down message MUST contain one of each of the
data items: following data items:
o MAC Address (Section 8.9) o MAC Address (Section 9.7)
7.12. Destination Down ACK Signal 8.12. Destination Down Response Message
A DLEP participant MUST send a Destination Down ACK signal to A DLEP participant MUST send a Destination Down Response message to
indicate whether a received Destination Down signal (Section 7.11) indicate whether a received Destination Down message (Section 8.11)
was successfully processed. If successfully processed, the sender of was successfully processed. If successfully processed, the sender of
the ACK MUST have removed all entries in the information base that the Response MUST have removed all entries in the information base
pertain to the referenced destination. that pertain to the referenced destination.
To construct a Destination Down ACK signal, the Signal Type value in To construct a Destination Down Response message, the Message Type
the signal header is set to DLEP_DEST_DOWN_ACK in Table 1. value in the message header is set to 12, from Table 1.
The Destination Down ACK signal MUST contain one of each of the The Destination Down Response message MUST contain one of each of the
following data items: following data items:
o MAC Address (Section 8.9) o MAC Address (Section 9.7)
The Destination Down Response message MAY contain one of each of the
The Destination Down ACK signal MAY contain one of each of the
following data items: following data items:
o Status (Section 8.2) o Status (Section 9.1)
A receiver of a Destination Down ACK signal without a Status data A receiver of a Destination Down Response message without a Status
item MUST behave as if a Status data item with status code 'Success' data item MUST behave as if a Status data item with status code
had been received. Implementations are free to define retry 'Success' had been received.
heuristics when receiving a Destination Down ACK signal indicating an
error.
7.13. Destination Update Signal 8.13. Destination Update Message
A DLEP participant SHOULD send the Destination Update signal when it A DLEP participant SHOULD send the Destination Update message when it
detects some change in the information base for a given destination detects some change in the information base for a given destination
(remote node or multicast group). Some examples of changes that (remote node or multicast group). Some examples of changes that
would prompt a Destination Update signal are: would prompt a Destination Update message are:
o Change in link metrics (e.g., Data Rates) o Change in link metrics (e.g., Data Rates)
o Layer 3 addressing change o Layer 3 addressing change
To construct a Destination Update signal, the Signal Type value in To construct a Destination Update message, the Message Type value in
the signal header is set to DLEP_DEST_UPDATE in Table 1. the message header is set to 13, from Table 1.
The Destination Update signal MUST contain one of each of the The Destination Update message MUST contain one of each of the
following data items: following data items:
o MAC Address (Section 8.9) o MAC Address (Section 9.7)
The Destination Update signal MAY contain one of each of the The Destination Update message MAY contain one of each of the
following data items: following data items:
o Maximum Data Rate (Receive) (Section 8.14) o Maximum Data Rate (Receive) (Section 9.12)
o Maximum Data Rate (Transmit) (Section 8.15)
o Current Data Rate (Receive) (Section 8.16) o Maximum Data Rate (Transmit) (Section 9.13)
o Current Data Rate (Transmit) (Section 8.17) o Current Data Rate (Receive) (Section 9.14)
o Latency (Section 8.18) o Current Data Rate (Transmit) (Section 9.15)
o Resources (Receive) (Section 8.19) o Latency (Section 9.16)
o Resources (Transmit) (Section 8.20) o Resources (Receive) (Section 9.17)
o Relative Link Quality (Receive) (Section 8.21) o Resources (Transmit) (Section 9.18)
o Relative Link Quality (Transmit) (Section 8.22) o Relative Link Quality (Receive) (Section 9.19)
The Destination Update signal MAY contain one or more of the o Relative Link Quality (Transmit) (Section 9.20)
The Destination Update message MAY contain one or more of the
following data items, with different values: following data items, with different values:
o IPv4 Address (Section 8.10) o IPv4 Address (Section 9.8)
o IPv6 Address (Section 8.11)
o IPv4 Attached Subnet (Section 8.12)
o IPv6 Attached Subnet (Section 8.13) o IPv6 Address (Section 9.9)
7.14. Heartbeat Signal 8.14. Heartbeat Message
A Heartbeat signal SHOULD be sent by a DLEP participant every N A Heartbeat message SHOULD be sent by a DLEP participant every N
seconds, where N is defined in the Heartbeat Interval data item of seconds, where N is defined in the Heartbeat Interval data item of
the Peer Initialization signal (Section 7.3) or Peer Initialization the Session Initialization message (Section 8.3) or Session
ACK signal (Section 7.4). Note that implementations setting the Initialization Response message (Section 8.4).
Heartbeat Interval to 0 effectively set the interval to an infinite
value, therefore, in those cases, this signal SHOULD NOT be sent.
The signal is used by participants to detect when a DLEP session Note that implementations setting the Heartbeat Interval to 0
effectively sets the interval to an infinite value, therefore this
message SHOULD NOT be sent.
The message is used by participants to detect when a DLEP session
partner (either the modem or the router) is no longer communicating. partner (either the modem or the router) is no longer communicating.
Participants SHOULD allow two (2) heartbeat intervals to expire with Participants SHOULD allow two (2) heartbeat intervals to expire with
no traffic on the router/modem session before initiating DLEP session no traffic on the router/modem session before initiating DLEP session
termination procedures. termination procedures.
To construct a Heartbeat signal, the Signal Type value in the signal To construct a Heartbeat message, the Message Type value in the
header is set to DLEP_PEER_HEARTBEAT in Table 1. message header is set to 14, from Table 1.
There are no valid data items for the Heartbeat signal. There are no valid data items for the Heartbeat message.
7.15. Link Characteristics Request Signal 8.15. Link Characteristics Request Message
The Link Characteristics Request signal MAY be sent by the router to The Link Characteristics Request message MAY be sent by the router to
request that the modem initiate changes for specific characteristics request that the modem initiate changes for specific characteristics
of the link. The request can reference either a real destination of the link. The request can reference either a real destination
(e.g., a remote node), or a logical destination (e.g., a multicast (e.g., a remote node), or a logical destination (e.g., a multicast
group) within the network. group) within the network.
The Link Characteristics Request signal MAY contain either a Current The Link Characteristics Request message MAY contain either a Current
Data Rate (CDRR or CDRT) data item to request a different datarate Data Rate (CDRR or CDRT) data item to request a different datarate
than what is currently allocated, a Latency data item to request that than what is currently allocated, a Latency data item to request that
traffic delay on the link not exceed the specified value, or both. A traffic delay on the link not exceed the specified value, or both. A
Link Characteristics ACK signal (Section 7.16) is required to Link Characteristics Response message (Section 8.16) is required to
complete the request. Issuing a Link Characteristics Request with complete the request. Issuing a Link Characteristics Request with
ONLY the MAC Address data item is a mechanism a peer MAY use to ONLY the MAC Address data item is a mechanism a peer MAY use to
request metrics (via the Link Characteristics ACK) from its partner. request metrics (via the Link Characteristics Response) from its
partner.
The sender of a Link Characteristics Request signal MAY attach a
timer to the request using the Link Characteristics ACK Timer data
item. If a Link Characteristics ACK signal is received after the
timer expires, the sender MUST NOT assume that the request succeeded.
Implementations are free to define their retry heuristics in event of The sender of a Link Characteristics Request message MAY attach a
a timeout. timer to the request using the Link Characteristics Response Timer
data item. If a Link Characteristics Response message is received
after the timer expires, the sender MUST NOT assume that the request
succeeded. Implementations are free to define their retry heuristics
in event of a timeout.
To construct a Link Characteristics Request signal, the Signal Type To construct a Link Characteristics Request message, the Message Type
value in the signal header is set to DLEP_LINK_CHAR_REQ in Table 1. value in the message header is set to 15, from Table 1.
The Link Characteristics Request signal MUST contain one of each of The Link Characteristics Request message MUST contain one of each of
the following data items: the following data items:
o MAC Address (Section 8.9) o MAC Address (Section 9.7)
The Link Characteristics Request signal MAY contain one of each of The Link Characteristics Request message MAY contain one of each of
the following data items: the following data items:
o Link Characteristics ACK Timer (Section 8.23) o Link Characteristics Response Timer (Section 9.21)
o Current Data Rate (Receive) (Section 8.16) o Current Data Rate (Receive) (Section 9.14)
o Current Data Rate (Transmit) (Section 8.17) o Current Data Rate (Transmit) (Section 9.15)
o Latency (Section 8.18) o Latency (Section 9.16)
7.16. Link Characteristics ACK Signal 8.16. Link Characteristics Response Message
A DLEP participant MUST send a Link Characteristics ACK signal to A DLEP participant MUST send a Link Characteristics Response message
indicate whether a received Link Characteristics Request signal to indicate whether a received Link Characteristics Request message
(Section 7.15) was successfully processed. The Link Characteristics (Section 8.15) was successfully processed. The Link Characteristics
ACK signal SHOULD contain a complete set of metric data items, and Response message SHOULD contain a complete set of metric data items,
MUST contain a full set (i.e. those declared in the Peer and MUST contain a full set (i.e. those declared in the Session
Initialization ACK signal (Section 7.4)), if metrics were requested Initialization Response message (Section 8.4)), if metrics were
by only including a MAC address data item. It MUST contain the same requested by only including a MAC address data item. It MUST contain
metric types as the request. The values in the metric data items in the same metric types as the request. The values in the metric data
the Link Characteristics ACK signal MUST reflect the link items in the Link Characteristics Response message MUST reflect the
characteristics after the request has been processed. link characteristics after the request has been processed.
If an implementation is not able to alter the characteristics of the If an implementation is not able to alter the characteristics of the
link in the manner requested, then a Status data item with status link in the manner requested, then a Status data item with status
code 'Request Denied' MUST be added to the signal. code 'Request Denied', see Table 3, MUST be added to the message.
To construct a Link Characteristics Request ACK signal, the Signal
Type value in the signal header is set to DLEP_LINK_CHAR_ACK in
Table 1.
The Link Characteristics ACK signal MUST contain one of each of the
following data items:
o MAC Address (Section 8.9)
The Link Characteristics ACK signal SHOULD contain one of each of the
following data items:
o Maximum Data Rate (Receive) (Section 8.14)
o Maximum Data Rate (Transmit) (Section 8.15)
o Current Data Rate (Receive) (Section 8.16)
o Current Data Rate (Transmit) (Section 8.17)
o Latency (Section 8.18) To construct a Link Characteristics Response message, the Message
Type value in the message header is set to 16, from Table 1.
The Link Characteristics ACK signal MAY contain one of each of the The Link Characteristics Response message MUST contain one of each of
following data items: the following data items:
o Resources (Receive) (Section 8.19) o MAC Address (Section 9.7)
o Resources (Transmit) (Section 8.20) The Link Characteristics Response message SHOULD contain one of each
of the following data items:
o Relative Link Quality (Receive) (Section 8.21) o Maximum Data Rate (Receive) (Section 9.12)
o Relative Link Quality (Transmit) (Section 8.22) o Maximum Data Rate (Transmit) (Section 9.13)
o Status (Section 8.2) o Current Data Rate (Receive) (Section 9.14)
A receiver of a Link Characteristics ACK signal without a Status data o Current Data Rate (Transmit) (Section 9.15)
item MUST behave as if a Status data item with status code 'Success'
had been received.
8. DLEP Data Items o Latency (Section 9.16)
Following is the list of MANDATORY data items that must be recognized The Link Characteristics Response message MAY contain one of each of
by a DLEP compliant implementation. As mentioned before, not all the following data items:
data items need be used during a session, but an implementation MUST
correctly process these data items when correctly associated with a
signal.
The DLEP data items are: o Resources (Receive) (Section 9.17)
+------------+--------------------------------------+---------------+ o Resources (Transmit) (Section 9.18)
| Data Item | Description | Section |
+------------+--------------------------------------+---------------+
| TBD | DLEP Version | Section 8.1 |
| TBD | Status | Section 8.2 |
| TBD | IPv4 Connection Point | Section 8.3 |
| TBD | IPv6 Connection Point | Section 8.4 |
| TBD | Peer Type | Section 8.5 |
| TBD | Heartbeat Interval | Section 8.6 |
| TBD | Extensions Supported | Section 8.7 |
| TBD | Experimental Definition | Section 8.8 |
| TBD | MAC Address | Section 8.9 |
| TBD | IPv4 Address | Section 8.10 |
| TBD | IPv6 Address | Section 8.11 |
| TBD | IPv4 Attached Subnet | Section 8.12 |
| TBD | IPv6 Attached Subnet | Section 8.13 |
| TBD | Maximum Data Rate (Receive) MDRR) | Section 8.14 |
| TBD | Maximum Data Rate (Transmit) (MDRT) | Section 8.15 |
| TBD | Current Data Rate (Receive) (CDRR) | Section 8.16 |
| TBD | Current Data Rate (Transmit) (CDRT) | Section 8.17 |
| TBD | Latency | Section 8.18 |
| TBD | Resources (Receive) (RESR) | Section 8.19 |
| TBD | Resources (Transmit) (REST) | Section 8.20 |
| TBD | Relative Link Quality (Receive) | Section 8.21 |
| | (RLQR) | |
| TBD | Relative Link Quality (Transmit) | Section 8.22 |
| | (RLQT) | |
| TBD | Link Characteristics ACK Timer | Section 8.23 |
+------------+--------------------------------------+---------------+
Table 2: DLEP Data Item Values o Relative Link Quality (Receive) (Section 9.19)
8.1. DLEP Version o Relative Link Quality (Transmit) (Section 9.20)
The DLEP Version data item MUST appear in the Peer Discovery o Status (Section 9.1)
(Section 7.1), Peer Offer (Section 7.2), Peer Initialization
(Section 7.3) and Peer Initialization ACK (Section 7.4) signals. The
Version data item is used to indicate the version of the protocol
running in the originator. A DLEP implementation SHOULD use this
information to decide if the potential session partner is running at
a supported level.
The DLEP Version data item contains the following fields: A receiver of a Link Characteristics Response message without a
Status data item MUST behave as if a Status data item with status
code 'Success' had been received.
0 1 2 3 9. DLEP Data Items
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Major Version |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Minor Version |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Following is the list of core data items that MUST be recognized by a
DLEP compliant implementation. As mentioned before, not all data
items need be used during a session, but an implementation MUST
correctly process these data items when correctly associated with a
signal or message.
Length: 4 The core DLEP data items are:
Major Version: The major version of the DLEP protocol, expressed as +-------------+-----------------------------------------------------+
an 16-bit unsigned integer. | Type Code | Description |
+-------------+-----------------------------------------------------+
| 0 | Reserved |
| 1 | Status (Section 9.1) |
| 2 | IPv4 Connection Point (Section 9.2) |
| 3 | IPv6 Connection Point (Section 9.3) |
| 4 | Peer Type (Section 9.4) |
| 5 | Heartbeat Interval (Section 9.5) |
| 6 | Extensions Supported (Section 9.6) |
| 7 | MAC Address (Section 9.7) |
| 8 | IPv4 Address (Section 9.8) |
| 9 | IPv6 Address (Section 9.9) |
| 10 | IPv4 Attached Subnet (Section 9.10) |
| 11 | IPv6 Attached Subnet (Section 9.11) |
| 12 | Maximum Data Rate (Receive) MDRR) (Section 9.12) |
| 13 | Maximum Data Rate (Transmit) (MDRT) (Section 9.13) |
| 14 | Current Data Rate (Receive) (CDRR) (Section 9.14) |
| 15 | Current Data Rate (Transmit) (CDRT) (Section 9.15) |
| 16 | Latency (Section 9.16) |
| 17 | Resources (Receive) (RESR) (Section 9.17) |
| 18 | Resources (Transmit) (REST) (Section 9.18) |
| 19 | Relative Link Quality (Receive) (RLQR) (Section |
| | 9.19) |
| 20 | Relative Link Quality (Transmit) (RLQT) (Section |
| | 9.20) |
| 21 | Link Characteristics Response Timer (Section 9.21) |
| 22-24 | Credit Windowing (Section 10) extension data items |
| 25-65407 | Reserved for future extensions |
| 65408-65534 | Private Use. Available for experiments |
| 65535 | Reserved |
+-------------+-----------------------------------------------------+
Minor Version: The minor version of the DLEP protocol, expressed as Table 2: DLEP Data Item types
an 16-bit unsigned integer.
Support of this draft is indicated by setting the Major Version to 9.1. Status
'1', and the Minor Version to '0' (i.e. Version 1.0).
8.2. Status The Status data item MAY appear in the Session Initialization
Response (Section 8.4), Session Termination (Section 8.7), Session
Termination Response (Section 8.8), Session Update Response
(Section 8.6), Destination Up Response (Section 8.10), Destination
Down Response (Section 8.12) and Link Characteristics Response
(Section 8.16) messages.
The Status data item MAY appear in the Peer Initialization ACK For the Session Termination message (Section 8.7), the Status data
(Section 7.4), Peer Termination (Section 7.7), Peer Termination ACK item indicates a reason for the termination. For all acknowledgement
(Section 7.8), Peer Update ACK (Section 7.6), Destination Up ACK messages, the Status data item is used to indicate the success or
(Section 7.10), Destination Down ACK (Section 7.12) and Link failure of the previously received message.
Characteristics ACK (Section 7.16) signals. For the Peer Termination
Signal (Section 7.7), the Status data item indicates a reason for the
termination. For all acknowledgement signals, the Status data item
is used to indicate the success or failure of the previously received
signal.
The status data item includes an optional Text field that can be used The status data item includes an optional Text field that can be used
to provide a textual description of the status. The use of the Text to provide a textual description of the status. The use of the Text
field is entirely up to the receiving implementation, i.e., it could field is entirely up to the receiving implementation, i.e., it could
be output to a log file or discarded. If no Text field is supplied be output to a log file or discarded. If no Text field is supplied
with the Status data item, the Length field MUST be set to 1. with the Status data item, the Length field MUST be set to 1.
The Status data item contains the following fields: The Status data item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Code | Text... | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Code | Text... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 1 + Length of text
Status Code: One of the codes defined below. Length: 1 + Length of text, in octets
Text: UTF-8 encoded string, describing an problem, used for Status Code: One of the codes defined in Table 3 below.
implementation defined purposes. Since this field is used for a
description of the problem, implementations SHOULD limit Text: UTF-8 encoded string, describing the cause, used for
characters in this field to printable characters. Implementations implementation defined purposes. Since this field is used for
receiving this data item SHOULD check for printable characters in description, implementations SHOULD limit characters in this field
the field. to printable characters. Implementations receiving this data item
SHOULD check for printable characters in the field.
An implementation MUST NOT assume the Text field is NUL-terminated. An implementation MUST NOT assume the Text field is NUL-terminated.
+----------------+-------+------------------------------------------+ +-------------+---------+-----------+-------------------------------+
| Status Code | Value | Reason | | Status Code | Value | Failure | Reason |
+----------------+-------+------------------------------------------+ | | | Mode | |
| Success | 0 | The signal was processed successfully. | +-------------+---------+-----------+-------------------------------+
| Unknown Signal | TBD | The signal was not recognized by the | | Success | 0 | Success | The message was processed |
| | | implementation. | | | | | successfully. |
| Invalid Data | TBD | One or more data items in the signal are | | Unknown | 1 | Terminate | The message was not |
| | | invalid, unexpected or duplicated. | | Message | | | recognized by the |
| Unexpected | TBD | The signal was not expected while the | | | | | implementation. |
| Signal | | machine was in this state, e.g., a Peer | | Unexpected | 2 | Terminate | The message was not expected |
| | | Initialization signal after session | | Message | | | while the device was in the |
| | | establishment. | | | | | current state, e.g., a |
| Request Denied | TBD | The receiver has not completed the | | | | | Session Initialization |
| | | request. | | | | | message (Section 8.3) in the |
| Timed Out | TBD | The request could not be completed in | | | | | In-Session state. |
| | | the time allowed. | | Invalid | 3 | Terminate | One or more data items in the |
| Invalid | TBD | The destination provided in the signal | | Data | | | message are invalid, |
| Destination | | does not match a previously announced | | | | | unexpected or incorrectly |
| | | destination. For example, in the Link | | | | | duplicated. |
| | | Characteristic Request ACK signal | | Invalid | 4 | Terminate | The destination provided in |
| | | (Section 7.16). | | Destination | | | the message does not match a |
+----------------+-------+------------------------------------------+ | | | | previously announced |
| | | | destination. For example, in |
| | | | the Link Characteristic |
| | | | Response message (Section |
| | | | 8.16). |
| <Reserved> | 5-90 | Terminate | Reserved for future |
| | | | extensions. |
| <Private | 91-99 | Terminate | Available for experiments. |
| Use> | | | |
| Not | 100 | Continue | The receiver is not |
| Interested | | | interested in this message |
| | | | subject, e.g. a Destination |
| | | | Up Response message (Section |
| | | | 8.10) to indicate no further |
| | | | messages about the |
| | | | destination. |
| Request | 101 | Continue | The receiver refuses to |
| Denied | | | complete the request. |
| Timed Out | 102 | Continue | The operation could not be |
| | | | completed in the time |
| | | | allowed. |
| <Reserved> | 103-243 | Continue | Reserved for future |
| | | | extensions. |
| <Private | 244-254 | Continue | Available for experiments. |
| Use> | | | |
| <Reserved> | 255 | Terminate | Reserved. |
+-------------+---------+-----------+-------------------------------+
8.3. IPv4 Connection Point Table 3: DLEP Status Codes
A failure mode of 'Terminate' indicates that the session MUST be
terminated after sending a response containing the status code. A
failure mode of 'Continue' indicates that the session SHOULD continue
as normal.
9.2. IPv4 Connection Point
The IPv4 Connection Point data item MAY appear in the Peer Offer The IPv4 Connection Point data item MAY appear in the Peer Offer
signal (Section 7.2). The IPv4 Connection Point data item indicates signal (Section 8.2).
the IPv4 address and, optionally, the TCP port number on the DLEP
modem available for connections. If provided, the receiver MUST use The IPv4 Connection Point data item indicates the IPv4 address and,
this information to perform the TCP connect to the DLEP server. optionally, the TCP port number on the DLEP modem available for
connections. If provided, the receiver MUST use this information to
perform the TCP connect to the DLEP server.
The IPv4 Connection Point data item contains the following fields: The IPv4 Connection Point data item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | IPv4 Address | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address | TCP Port Number (optional) | | IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TCP Port Number (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 4 (or 6 if TCP Port included) Length: 4 (or 6 if TCP Port included)
IPv4 Address: The IPv4 address listening on the DLEP modem. IPv4 Address: The IPv4 address listening on the DLEP modem.
TCP Port Number: TCP Port number on the DLEP modem. TCP Port Number: TCP Port number on the DLEP modem.
If the Length field is 6, the port number specified MUST be used to If the Length field is 6, the port number specified MUST be used to
establish the TCP session. If the TCP Port Number is omitted, i.e. establish the TCP session. If the TCP Port Number is omitted, i.e.
the Length field is 4, the receiver MUST use the DLEP well-known port the Length field is 4, the receiver MUST use the DLEP well-known port
number (Section 11.7) to establish the TCP connection. number (Section 12.7) to establish the TCP connection.
8.4. IPv6 Connection Point 9.3. IPv6 Connection Point
The IPv6 Connection Point data item MAY appear in the Peer Offer The IPv6 Connection Point data item MAY appear in the Peer Offer
signal (Section 7.2). The IPv6 Connection Point data item indicates signal (Section 8.2).
the IPv6 address and, optionally, the TCP port number on the DLEP
modem available for connections. If provided, the receiver MUST use The IPv6 Connection Point data item indicates the IPv6 address and,
this information to perform the TCP connect to the DLEP server. optionally, the TCP port number on the DLEP modem available for
connections. If provided, the receiver MUST use this information to
perform the TCP connect to the DLEP server.
The IPv6 Connection Point data item contains the following fields: The IPv6 Connection Point data item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | IPv6 Address | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Address | : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Address | : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Address | : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Address | TCP Port Number (optional) | : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TCP Port Number (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 16 (or 18 if TCP Port included) Length: 16 (or 18 if TCP Port included)
IPv6 Address: The IPv6 address listening on the DLEP modem. IPv6 Address: The IPv6 address listening on the DLEP modem.
TCP Port Number: TCP Port number on the DLEP modem. TCP Port Number: TCP Port number on the DLEP modem.
If the Length field is 18, the port number specified MUST be used to If the Length field is 18, the port number specified MUST be used to
establish the TCP session. If the TCP Port Number is omitted, i.e. establish the TCP session. If the TCP Port Number is omitted, i.e.
the Length field is 16, the receiver MUST use the DLEP well-known the Length field is 16, the receiver MUST use the DLEP well-known
port number (Section 11.7) to establish the TCP connection. port number (Section 12.7) to establish the TCP connection.
8.5. Peer Type 9.4. Peer Type
The Peer Type data item MAY appear in the Peer Discovery The Peer Type data item MAY appear in the Peer Discovery
(Section 7.1), Peer Offer (Section 7.2), Peer Initialization (Section 8.1) and Peer Offer (Section 8.2) signals, and the Session
(Section 7.3) and Peer Initialization ACK (Section 7.4) signals. The Initialization (Section 8.3) and Session Initialization Response
Peer Type data item is used by the router and modem to give (Section 8.4) messages.
The Peer Type data item is used by the router and modem to give
additional information as to its type. The peer type is a string and additional information as to its type. The peer type is a string and
is envisioned to be used for informational purposes (e.g., as output is envisioned to be used for informational purposes (e.g., as output
in a display command). in a display command).
The Peer Type data item contains the following fields: The Peer Type data item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Peer Type | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peer Type... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: Length of peer type string. Length: Length of peer type string, in octets.
Peer Type: UTF-8 encoded string. For example, a satellite modem Peer Type: UTF-8 encoded string. For example, a satellite modem
might set this variable to "Satellite terminal". Since this data might set this variable to "Satellite terminal". Since this data
item is intended to provide additional information for display item is intended to provide additional information for display
commands, sending implementations SHOULD limit the data to commands, sending implementations SHOULD limit the data to
printable characters, and receiving implmentations SHOULD check printable characters, and receiving implmentations SHOULD check
the data for printable characters. the data for printable characters.
An implementation MUST NOT assume the Peer Type field is NUL- An implementation MUST NOT assume the Peer Type field is NUL-
terminated. terminated.
8.6. Heartbeat Interval 9.5. Heartbeat Interval
The Heartbeat Interval data item MUST appear in both the Peer The Heartbeat Interval data item MUST appear in both the Session
Initialization (Section 7.3) and Peer Initialization ACK Initialization (Section 8.3) and Session Initialization Response
(Section 7.4) signals to indicate the Heartbeat timeout window to be (Section 8.4) messages to indicate the Heartbeat timeout window to be
used by the sender. used by the sender.
The Interval is used to specify a period (in seconds) for Heartbeat The Interval is used to specify a period (in seconds) for Heartbeat
signals (Section 7.14). By specifying an Interval value of 0, messages (Section 8.14). By specifying an Interval value of 0,
implementations MAY indicate the desire to disable Heartbeat signals implementations MAY indicate the desire to disable Heartbeat messages
entirely (i.e., the Interval is set to an infinite value). However, entirely (i.e., the Interval is set to an infinite value). However,
it is strongly recommended that implementations use non-0 timer it is RECOMMENDED that implementations use non-0 timer values.
values. Implementations MUST implement heuristics such that DLEP
signals sent/received reset the timer interval.
A DLEP session will be considered inactive, and MUST be torn down,
via the Peer Termination procedure, by an implementation detecting
that two (2) Heartbeat intervals have transpired without receipt of
any DLEP signals.
The Heartbeat Interval data item contains the following fields: The Heartbeat Interval data item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Interval | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 2 Length: 2
Interval: 0 = Do not use heartbeats on this DLEP session. Non-zero
= Interval, in seconds, for heartbeat messages.
Interval: 0 = Do NOT use heartbeats on this DLEP session. Non-zero 9.6. Extensions Supported
= Interval, in seconds, for heartbeat signals.
8.7. Extensions Supported The Extensions Supported data item MAY be used in both the Session
Initialization (Section 8.3) and Session Initialization Response
(Section 8.4) messages.
The Extensions Supported data item MAY be used in both the Peer The Extensions Supported data item is used by the router and modem to
Initialization and Peer Initialization ACK signals. The Extensions negotiate additional optional functionality they are willing to
Supported data item is used by the router and modem to negotiate support. The Extensions List is a concatenation of the types of each
additional optional functionality they are willing to support. The supported extension, found in the IANA DLEP Extensions repository.
Extensions List is a concatenation of the types of each supported Each Extension Type definition includes which additional signals and
extension, found in the IANA DLEP Extensions repository. data-items are supported.
The Extensions Supported data item contains the following fields: The Extensions Supported data item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Extensions List | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extensions List...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: Number of Extensions supported. Length: Length of the extensions list in octets. This is twice (2x)
the number of extensions.
Extension List: A list of extensions supported, identified by their Extension List: A list of extensions supported, identified by their
1-octet value as listed in the extensions registry. 2-octet value as listed in the extensions registry.
8.8. Experimental Definition 9.7. MAC Address
The Experimental Definition data item MAY be used in both the Peer The MAC address data item MUST appear in all destination-oriented
Initialization and Peer Initialization ACK signals. The Experimental messages (i.e., Destination Up (Section 8.9), Destination Up Response
Definition data item is used by the router and modem to indicate the (Section 8.10), Destination Down (Section 8.11), Destination Down
formats to be used for experimental signals and data items for the Response (Section 8.12), Destination Update (Section 8.13), Link
given peer session. The formats are identified by using a string Characteristics Request (Section 8.15), and Link Characteristics
that matches the 'name' given to the experiment. Response (Section 8.16)).
The Experimental Definition item contains the following fields: The MAC Address data item contains the address of the destination on
the remote node. The MAC address MAY be either a physical or a
virtual destination, and MAY be expressed in EUI-48 or EUI-64 format.
Examples of a virtual destination would be a multicast MAC address,
or the broadcast MAC (FF:FF:FF:FF:FF:FF).
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Experiment Name | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC Address :
Data Item Type: TBD
Length: Length of the name string for the Experiment.
Experiment Name: UTF-8 encoded string, containing the name of the
experiment being implemented.
An implementation receiving this data item MUST compare the received
string to a list of experiments that it supports.
An implementation MUST NOT assume the Experiment Name field is NUL-
terminated.
8.9. MAC Address
The MAC address data item MUST appear in all destination-oriented
signals (i.e., Destination Up (Section 7.9), Destination Up ACK
(Section 7.10), Destination Down (Section 7.11), Destination Down ACK
(Section 7.12), Destination Update (Section 7.13), Link
Characteristics Request (Section 7.15), and Link Characteristics ACK
(Section 7.16)). The MAC Address data item contains the address of
the destination on the remote node. The MAC address MAY be either a
physical or a virtual destination, and MAY be expressed in EUI-48 or
EUI-64 format. Examples of a virtual destination would be a
multicast MAC address, or the broadcast MAC (FF:FF:FF:FF:FF:FF).
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | MAC Address | : MAC Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC Address | : MAC Address : (if EUI-64 used) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 6 for EUI-48 format, or 8 for EUI-64 format Length: 6 for EUI-48 format, or 8 for EUI-64 format
MAC Address: MAC Address of the destination. MAC Address: MAC Address of the destination.
8.10. IPv4 Address 9.8. IPv4 Address
The IPv4 Address data item MAY appear in the Peer Update The IPv4 Address data item MAY appear in the Session Update
(Section 7.5), Destination Up (Section 7.9) and Destination Update (Section 8.5), Destination Up (Section 8.9) and Destination Update
(Section 7.13) signals. When included in Destination signals, this (Section 8.13) messages.
data item contains the IPv4 address of the destination. When
included in the Peer Update signal, this data item contains the IPv4 When included in Destination messages, this data item contains the
address of the peer. In either case, the data item also contains an IPv4 address of the destination. When included in the Session Update
indication of whether this is a new or existing address, or is a message, this data item contains the IPv4 address of the peer. In
deletion of a previously known address. either case, the data item also contains an indication of whether
this is a new or existing address, or is a deletion of a previously
known address.
The IPv4 Address data item contains the following fields: The IPv4 Address data item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Add/Drop | IPv4 Address | | Data Item Type | Length |
| | | Indicator | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address | | Add/Drop | IPv4 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Indicator | :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv4 |
: Address |
+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 5 Length: 5
Add/Drop: Value indicating whether this is a new or existing address Add/Drop: Value indicating whether this is a new or existing address
(1), or a withdrawal of an address (0). Values other than 0 or 1 (1), or a withdrawal of an address (0). Values other than 0 or 1
MUST be considered as invalid. MUST be considered as invalid.
IPv4 Address: The IPv4 address of the destination or peer. IPv4 Address: The IPv4 address of the destination or peer.
8.11. IPv6 Address 9.9. IPv6 Address
The IPv6 Address data item MAY appear in the Peer Update The IPv6 Address data item MAY appear in the Session Update
(Section 7.5), Destination Up (Section 7.9) and Destination Update (Section 8.5), Destination Up (Section 8.9) and Destination Update
(Section 7.13) signals. When included in Destination signals, this (Section 8.13) messages. When included in Destination messages, this
data item contains the IPv6 address of the destination. When data item contains the IPv6 address of the destination. When
included in the Peer Update signal, this data item contains the IPv6 included in the Session Update message, this data item contains the
address of the peer. In either case, the data item also contains an IPv6 address of the peer. In either case, the data item also
indication of whether this is a new or existing address, or is a contains an indication of whether this is a new or existing address,
deletion of a previously known address. or is a deletion of a previously known address.
The IPv6 Address data item contains the following fields: The IPv6 Address data item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Add/Drop | IPv6 Address | | Data Item Type | Length |
| | | Indicator | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Address | | Add/Drop | IPv6 Address :
| Indicator | :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Address | : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Address | : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Address | : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Address |
+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 17 Length: 17
Add/Drop: Value indicating whether this is a new or existing address Add/Drop: Value indicating whether this is a new or existing address
(1), or a withdrawal of an address (0). Values other than 0 or 1 (1), or a withdrawal of an address (0). Values other than 0 or 1
MUST be considered as invalid. MUST be considered as invalid.
IPv6 Address: IPv6 Address of the destination or peer. IPv6 Address: IPv6 Address of the destination or peer.
8.12. IPv4 Attached Subnet 9.10. IPv4 Attached Subnet
The DLEP IPv4 Attached Subnet allows a device to declare that it has The DLEP IPv4 Attached Subnet allows a device to declare that it has
an IPv4 subnet (e.g., a stub network) attached, or that it has become an IPv4 subnet (e.g., a stub network) attached, or that it has become
aware of an IPv4 subnet being present at a remote destination. The aware of an IPv4 subnet being present at a remote destination. The
IPv4 Attached Subnet data item MAY appear in the Destination Up IPv4 Attached Subnet data item MAY appear in the Destination Up
(Section 7.9) and Destination Update (Section 7.13) signals. Once an (Section 8.9) message. Once an IPv4 Subnet has been declared on a
IPv4 Subnet has been declared on a device, the declaration can NOT be device, the declaration SHALL NOT be withdrawn without withdrawing
withdrawn without terminating the destination (via the Destination the destination (via the Destination Down message (Section 8.11)) and
Down signal (Section 7.11)) and re-issuing the Destination Up signal. re-issuing the Destination Up message.
The DLEP IPv4 Attached Subnet data item contains the following The DLEP IPv4 Attached Subnet data item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Data Item Type | Length | IPv4 Attached Subnet | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Attached Subnet | Prefix Len. | | IPv4 Attached Subnet |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Len. |
+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 5 Length: 5
IPv4 Subnet: The IPv4 subnet reachable at the destination. IPv4 Subnet: The IPv4 subnet reachable at the destination.
Prefix Length: Length of the prefix (1-32) for the IPv4 subnet. A Prefix Length: Length of the prefix (1-32) for the IPv4 subnet. A
prefix length outside the speficied range MUST be considered as prefix length outside the speficied range MUST be considered as
invalid. invalid.
8.13. IPv6 Attached Subnet 9.11. IPv6 Attached Subnet
The DLEP IPv6 Attached Subnet allows a device to declare that it has The DLEP IPv6 Attached Subnet allows a device to declare that it has
an IPv6 subnet (e.g., a stub network) attached, or that it has become an IPv6 subnet (e.g., a stub network) attached, or that it has become
aware of an IPv6 subnet being present at a remote destination. The aware of an IPv6 subnet being present at a remote destination. The
IPv6 Attached Subnet data item MAY appear in the Destination Up IPv6 Attached Subnet data item MAY appear in the Destination Up
(Section 7.9) and Destination Update (Section 7.13) signals. As in (Section 8.9) message. As in the case of the IPv4 attached Subnet
the case of the IPv4 attached Subnet data item above, once an IPv6 data item above, once an IPv6 attached subnet has been declared, it
attached subnet has been declared, it can NOT be withdrawn without SHALL NOT be withdrawn without withdrawing the destination (via the
terminating the destination (via the Destination Down signal Destination Down message (Section 8.11)) and re-issuing the
(Section 7.11)) and re-issuing the Destination Up signal. Destination Up message.
The DLEP IPv6 Attached Subnet data item contains the following The DLEP IPv6 Attached Subnet data item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | IPv6 Attached Subnet | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Attached Subnet | | IPv6 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Attached Subnet | : IPv6 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Attached Subnet | : IPv6 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Attached Subnet | Prefix Len. | : IPv6 Attached Subnet |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Len. |
+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 17 Length: 17
IPv4 Subnet: The IPv6 subnet reachable at the destination. IPv4 Subnet: The IPv6 subnet reachable at the destination.
Prefix Length: Length of the prefix (1-128) for the IPv6 subnet. A Prefix Length: Length of the prefix (1-128) for the IPv6 subnet. A
prefix length outside the specified range MUST be considered as prefix length outside the specified range MUST be considered as
invalid. invalid.
8.14. Maximum Data Rate (Receive) 9.12. Maximum Data Rate (Receive)
The Maximum Data Rate (Receive) (MDRR) data item MUST appear in the The Maximum Data Rate (Receive) (MDRR) data item MUST appear in the
Peer Initialization ACK signal (Section 7.4), and MAY appear in the Session Initialization Response message (Section 8.4), and MAY appear
Peer Update (Section 7.5), Destination Up (Section 7.9), Destination in the Session Update (Section 8.5), Destination Up (Section 8.9),
Update (Section 7.13) and Link Characteristics ACK (Section 7.16) Destination Update (Section 8.13) and Link Characteristics Response
signals to indicate the maximum theoretical data rate, in bits per (Section 8.16) messages to indicate the maximum theoretical data
second, that can be achieved while receiving data on the link. rate, in bits per second, that can be achieved while receiving data
on the link.
The Maximum Data Rate (Receive) data item contains the following The Maximum Data Rate (Receive) data item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | MDRR (bps) | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MDRR (bps) | | MDRR (bps) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: MDRR (bps) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MDRR (bps) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 8 Length: 8
Maximum Data Rate (Receive): A 64-bit unsigned integer, representing Maximum Data Rate (Receive): A 64-bit unsigned integer, representing
the maximum theoretical data rate, in bits per second (bps), that the maximum theoretical data rate, in bits per second (bps), that
can be achieved while receiving on the link. can be achieved while receiving on the link.
8.15. Maximum Data Rate (Transmit) 9.13. Maximum Data Rate (Transmit)
The Maximum Data Rate (Transmit) (MDRT) data item MUST appear in the The Maximum Data Rate (Transmit) (MDRT) data item MUST appear in the
Peer Initialization ACK signal (Section 7.4), and MAY appear in the Session Initialization Response message (Section 8.4), and MAY appear
Peer Update (Section 7.5), Destination Up (Section 7.9), Destination in the Session Update (Section 8.5), Destination Up (Section 8.9),
Update (Section 7.13) and Link Characteristics ACK (Section 7.16) Destination Update (Section 8.13) and Link Characteristics Response
signals to indicate the maximum theoretical data rate, in bits per (Section 8.16) messages to indicate the maximum theoretical data
second, that can be achieved while transmitting data on the link. rate, in bits per second, that can be achieved while transmitting
data on the link.
The Maximum Data Rate (Transmit) data item contains the following The Maximum Data Rate (Transmit) data item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | MDRT (bps) | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MDRT (bps) | | MDRT (bps) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: MDRT (bps) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MDRT (bps) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 8 Length: 8
Maximum Data Rate (Transmit): A 64-bit unsigned integer, Maximum Data Rate (Transmit): A 64-bit unsigned integer,
representing the maximum theoretical data rate, in bits per second representing the maximum theoretical data rate, in bits per second
(bps), that can be achieved while transmitting on the link. (bps), that can be achieved while transmitting on the link.
8.16. Current Data Rate (Receive) 9.14. Current Data Rate (Receive)
The Current Data Rate (Receive) (CDRR) data item MUST appear in the The Current Data Rate (Receive) (CDRR) data item MUST appear in the
Peer Initialization ACK signal (Section 7.4), and MAY appear in the Session Initialization Response message (Section 8.4), and MAY appear
Peer Update (Section 7.5), Destination Up (Section 7.9), Destination in the Session Update (Section 8.5), Destination Up (Section 8.9),
Update (Section 7.13) and Link Characteristics ACK (Section 7.16) Destination Update (Section 8.13) and Link Characteristics Response
signals to indicate the rate at which the link is currently operating (Section 8.16) messages to indicate the rate at which the link is
for receiving traffic. currently operating for receiving traffic.
When used in the Link Characteristics Request signal (Section 7.15), When used in the Link Characteristics Request message (Section 8.15),
CDRR represents the desired receive rate, in bits per second, on the CDRR represents the desired receive rate, in bits per second, on the
link. link.
The Current Data Rate (Receive) data item contains the following The Current Data Rate (Receive) data item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | CDRR (bps) | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CDRR (bps) | | CDRR (bps) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: CDRR (bps) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CDRR (bps) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 8 Length: 8
Current Data Rate (Receive): A 64-bit unsigned integer, representing Current Data Rate (Receive): A 64-bit unsigned integer, representing
the current data rate, in bits per second, that can currently be the current data rate, in bits per second, that can currently be
achieved while receiving traffic on the link. achieved while receiving traffic on the link.
If there is no distinction between current and maximum receive data If there is no distinction between current and maximum receive data
rates, current data rate receive MUST be set equal to the maximum rates, current data rate receive MUST be set equal to the maximum
data rate receive. data rate receive.
8.17. Current Data Rate (Transmit) 9.15. Current Data Rate (Transmit)
The Current Data Rate Transmit (CDRT) data item MUST appear in the The Current Data Rate Transmit (CDRT) data item MUST appear in the
Peer Initialization ACK signal (Section 7.4), and MAY appear in the Session Initialization Response message (Section 8.4), and MAY appear
Peer Update (Section 7.5), Destination Up (Section 7.9), Destination in the Session Update (Section 8.5), Destination Up (Section 8.9),
Update (Section 7.13), and Link Characteristics ACK (Section 7.16) Destination Update (Section 8.13), and Link Characteristics Response
signals to indicate the rate at which the link is currently operating (Section 8.16) messages to indicate the rate at which the link is
for transmitting traffic. currently operating for transmitting traffic.
When used in the Link Characteristics Request signal (Section 7.15), When used in the Link Characteristics Request message (Section 8.15),
CDRT represents the desired transmit rate, in bits per second, on the CDRT represents the desired transmit rate, in bits per second, on the
link. link.
The Current Data Rate (Transmit) data item contains the following The Current Data Rate (Transmit) data item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | CDRT (bps) | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CDRT (bps) | | CDRT (bps) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: CDRT (bps) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CDRT (bps) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 8 Length: 8
Current Data Rate (Transmit): A 64-bit unsigned integer, Current Data Rate (Transmit): A 64-bit unsigned integer,
representing the current data rate, in bits per second, that can representing the current data rate, in bits per second, that can
currently be achieved while transmitting traffic on the link. currently be achieved while transmitting traffic on the link.
If there is no distinction between current and maximum transmit data If there is no distinction between current and maximum transmit data
rates, current data rate transmit MUST be set equal to the maximum rates, current data rate transmit MUST be set equal to the maximum
data rate transmit. data rate transmit.
8.18. Latency 9.16. Latency
The Latency data item MUST appear in the Peer Initialization ACK The Latency data item MUST appear in the Session Initialization
signal (Section 7.4), and MAY appear in the Peer Update Response message (Section 8.4), and MAY appear in the Session Update
(Section 7.5), Destination Up (Section 7.9), Destination Update (Section 8.5), Destination Up (Section 8.9), Destination Update
(Section 7.13), and Link Characteristics ACK (Section 7.16) signals (Section 8.13), and Link Characteristics Response (Section 8.16)
to indicate the amount of latency, in microseconds, on the link. messages to indicate the amount of latency, in microseconds, on the
link.
When used in the Link Characteristics Request signal (Section 7.15), When used in the Link Characteristics Request message (Section 8.15),
Latency represents the maximum latency desired on the link. Latency represents the maximum latency desired on the link.
The Latency value is reported as delay. The calculation of latency The Latency value is reported as delay. The calculation of latency
is implementation dependent. For example, the latency may be a is implementation dependent. For example, the latency may be a
running average calculated from the internal queuing. running average calculated from the internal queuing.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Latency | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Latency (cont.) | | Latency :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Latency |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Latency (cont.) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 8 Length: 8
Latency: A 64-bit unsigned integer, representing the transmission Latency: A 64-bit unsigned integer, representing the transmission
delay, in microseconds, that a packet encounters as it is delay, in microseconds, that a packet encounters as it is
transmitted over the link. transmitted over the link.
8.19. Resources (Receive) 9.17. Resources (Receive)
The Resources (Receive) (RESR) data item MAY appear in the Peer The Resources (Receive) (RESR) data item MAY appear in the Session
Initialization ACK signal (Section 7.4), Peer Update (Section 7.5), Initialization Response message (Section 8.4), Session Update
Destination Up (Section 7.9), Destination Update (Section 7.13) and (Section 8.5), Destination Up (Section 8.9), Destination Update
Link Characteristics ACK (Section 7.16) signals to indicate the (Section 8.13) and Link Characteristics Response (Section 8.16)
amount of resources for reception (with 0 meaning 'no resources messages to indicate the amount of resources for reception (with 0
available', and 100 meaning 'all resources available') at the meaning 'no resources available', and 100 meaning 'all resources
destination. The list of resources that might be considered is available') at the destination. The list of resources that might be
beyond the scope of this document, and is left to implementations to considered is beyond the scope of this document, and is left to
decide. implementations to decide.
The Resources (Receive) data item contains the following fields: The Resources (Receive) data item contains the following fields:
0 1 2 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | RESR | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESR |
+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 1 Length: 1
Resources (Receive): An 8-bit integer percentage, 0-100, Resources (Receive): An 8-bit integer percentage, 0-100,
representing the amount of resources allocated to receiving data. representing the amount of resources allocated to receiving data.
Any value greater than 100 MUST be considered as invalid. Any value greater than 100 MUST be considered as invalid.
If a device cannot calculate RESR, this data item SHOULD NOT be If a device cannot calculate RESR, this data item SHOULD NOT be
issued. issued.
8.20. Resources (Transmit) 9.18. Resources (Transmit)
The Resources (Transmit) (REST) data item MAY appear in the Peer The Resources (Transmit) (REST) data item MAY appear in the Session
Initialization ACK signal (Section 7.4), Peer Update (Section 7.5), Initialization Response message (Section 8.4), Session Update
Destination Up (Section 7.9), Destination Update (Section 7.13) and (Section 8.5), Destination Up (Section 8.9), Destination Update
Link Characteristics ACK (Section 7.16) signals to indicate the (Section 8.13) and Link Characteristics Response (Section 8.16)
amount of resources for transmission (with 0 meaning 'no resources messages to indicate the amount of resources for transmission (with 0
available', and 100 meaning 'all resources available') at the meaning 'no resources available', and 100 meaning 'all resources
destination. The list of resources that might be considered is available') at the destination. The list of resources that might be
beyond the scope of this document, and is left to implementations to considered is beyond the scope of this document, and is left to
decide. implementations to decide.
The Resources (Transmit) data item contains the following fields: The Resources (Transmit) data item contains the following fields:
0 1 2 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | REST | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| REST |
+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 1 Length: 1
Resources (Transmit): An 8-bit integer percentage, 0-100, Resources (Transmit): An 8-bit integer percentage, 0-100,
representing the amount of resources allocated to transmitting representing the amount of resources allocated to transmitting
data. Any value greater than 100 MUST be considered as invalid. data. Any value greater than 100 MUST be considered as invalid.
If a device cannot calculate REST, this data item SHOULD NOT be If a device cannot calculate REST, this data item SHOULD NOT be
issued. issued.
8.21. Relative Link Quality (Receive) 9.19. Relative Link Quality (Receive)
The Relative Link Quality (Receive) (RLQR) data item MAY appear in The Relative Link Quality (Receive) (RLQR) data item MAY appear in
the Peer Initialization ACK signal (Section 7.4), Peer Update the Session Initialization Response message (Section 8.4), Session
(Section 7.5), Destination Up (Section 7.9), Destination Update Update (Section 8.5), Destination Up (Section 8.9), Destination
(Section 7.13) and Link Characteristics ACK (Section 7.16) signals to Update (Section 8.13) and Link Characteristics Response
indicate the quality of the link for receiving data. (Section 8.16) messages to indicate the quality of the link for
receiving data.
The Relative Link Quality (Receive) data item contains the following The Relative Link Quality (Receive) data item contains the following
fields: fields:
0 1 2 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | RLQR | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RLQR |
+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 1 Length: 1
Relative Link Quality (Receive): A non-dimensional 8-bit integer, Relative Link Quality (Receive): A non-dimensional 8-bit integer,
0-100, representing relative link quality. A value of 100 0-100, representing relative link quality. A value of 100
represents a link of the highest quality. Any value greater than represents a link of the highest quality. Any value greater than
100 MUST be considered as invalid. 100 MUST be considered as invalid.
If a device cannot calculate the RLQR, this data item SHOULD NOT be If a device cannot calculate the RLQR, this data item SHOULD NOT be
issued. issued.
8.22. Relative Link Quality (Transmit) 9.20. Relative Link Quality (Transmit)
The Relative Link Quality (Transmit) (RLQT) data item MAY appear in The Relative Link Quality (Transmit) (RLQT) data item MAY appear in
the Peer Initialization ACK signal (Section 7.4), Peer Update the Session Initialization Response message (Section 8.4), Session
(Section 7.5), Destination Up (Section 7.9), Destination Update Update (Section 8.5), Destination Up (Section 8.9), Destination
(Section 7.13) and Link Characteristics ACK (Section 7.16) signals to Update (Section 8.13) and Link Characteristics Response
indicate the quality of the link for transmitting data. (Section 8.16) messages to indicate the quality of the link for
transmitting data.
The Relative Link Quality (Transmit) data item contains the following The Relative Link Quality (Transmit) data item contains the following
fields: fields:
0 1 2 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | RLQT | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RLQT |
+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 1 Length: 1
Relative Link Quality (Transmit): A non-dimensional 8-bit integer, Relative Link Quality (Transmit): A non-dimensional 8-bit integer,
0-100, representing relative link quality. A value of 100 0-100, representing relative link quality. A value of 100
represents a link of the highest quality. Any value greater than represents a link of the highest quality. Any value greater than
100 MUST be considered as invalid. 100 MUST be considered as invalid.
If a device cannot calculate the RLQT, this data item SHOULD NOT be If a device cannot calculate the RLQT, this data item SHOULD NOT be
issued. issued.
8.23. Link Characteristics ACK Timer 9.21. Link Characteristics Response Timer
The Link Characteristics ACK Timer data item MAY appear in the Link The Link Characteristics Response Timer data item MAY appear in the
Characteristics Request signal (Section 7.15) to indicate the desired Link Characteristics Request message (Section 8.15) to indicate the
number of seconds the sender will wait for a response to the request. desired number of seconds the sender will wait for a response to the
If this data item is omitted, implementations supporting the Link request. If this data item is omitted, implementations supporting
Characteristics Request SHOULD choose a default value. the Link Characteristics Request SHOULD choose a default value.
The Link Characteristics ACK Timer data item contains the following The Link Characteristics Response Timer data item contains the
fields: following fields:
0 1 2 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Interval | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interval |
+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 1 Length: 1
Interval: 0 = Do NOT use timeouts for this Link Characteristics Interval: 0 = Do not use timeouts for this Link Characteristics
request. Non-zero = Interval, in seconds, to wait before request. Non-zero = Interval, in seconds, to wait before
considering this Link Characteristics Request lost. considering this Link Characteristics Request lost.
9. Credit-Windowing 10. Credit-Windowing
DLEP includes an OPTIONAL Protocol Extension for a credit-windowing DLEP includes an optional Protocol Extension for a credit-windowing
scheme analogous to the one documented in [RFC5578]. In this scheme, scheme analogous to the one documented in [RFC5578]. In this scheme,
traffic between the router and modem is treated as two unidirectional data plane traffic flowing between the router and modem is controlled
windows. This document identifies these windows as the 'Modem by the availability of credits. Credits are expressed as if two
Receive Window' (MRW), and the 'Router Receive Window' (RRW). unidirectional windows exist between the modem and router. This
document identifies these windows as the 'Modem Receive Window'
(MRW), and the 'Router Receive Window' (RRW).
If the OPTIONAL credit-windowing extension is used, credits MUST be If the credit-windowing extension is used, credits MUST be granted by
granted by the receiver on a given window - that is, on the 'Modem the receiver on a given window - that is, on the 'Modem Receive
Receive Window' (MRW), the modem is responsible for granting credits Window' (MRW), the modem is responsible for granting credits to the
to the router, allowing it (the router) to send data to the modem. router, allowing it (the router) to send data plane traffic to the
Likewise, the router is responsible for granting credits on the RRW, modem. Likewise, the router is responsible for granting credits on
which allows the modem to send data to the router. the RRW, which allows the modem to send data plane traffic to the
router.
Credits are managed on a destination-specific basis; that is, Credits are managed on a destination-specific basis; that is,
separate credit counts are maintained for each destination requiring separate credit counts are maintained for each destination requiring
the service. Credits do not apply to the DLEP session that exists the service. Credits do not apply to the DLEP session that exists
between routers and modems. between routers and modems; they are applied only to the data plane
traffic.
Credits represent the number of octets, or an increment in the number Credits represent the number of octets, or an increment in the number
of octets, that MAY be sent on the given window. When the number of of octets, that MAY be sent on the given window. When sending data
available credits reaches 0, a sender MUST stop sending data, until plane traffic to a credit-enabled peer, the sender MUST decriment the
additional credits are supplied. appropriate window by the size of the data being sent. For example,
when sending data plane traffic via the modem, the router MUST
decriment the 'Modem Receive Window' (MRW) for the corresponding
destination. When the number of available credits to the destination
reaches 0, a sender MUST stop sending data plane traffic to the
destination, until additional credits are supplied.
If a peer is able to support the OPTIONAL credit-windowing extension If a peer is able to support the optional credit-windowing extension
then it MUST include an Extensions Supported data item (Section 8.7) then it MUST include an Extensions Supported data item (Section 9.6)
including the value DLEP_EXT_CREDITS (value TBD) in the appropriate including the value 1, from Table 4, in the appropriate Session
Peer Initialization or Peer Initialization ACK signal. Initialization (Section 8.3) and Session Initialization Response
(Section 8.4) message.
9.1. Credit-Windowing Signals 10.1. Credit-Windowing Messages
The credit-windowing extension introduces no additional DLEP signals. The credit-windowing extension introduces no additional DLEP signals
However, if a peer has advertised during session initialization that or messages. However, if a peer has advertised during session
it supports the credit-windowing extension then the following DLEP initialization that it supports the credit-windowing extension then
signals MAY contain additional credit-windowing data items: the following DLEP messages MAY contain additional credit-windowing
data items:
9.1.1. Destination Up Signal 10.1.1. Destination Up Message
The Destination Up signal MAY contain one of each of the following The Destination Up message MAY contain one of each of the following
data items: data items:
o Credit Grant (Section 9.2.1) o Credit Grant (Section 10.2.1)
If the Destination Up signal does not contain the Credit Grant data If the Destination Up message does not contain the Credit Grant data
item, credits MUST NOT be used for that destination. item, credits MUST NOT be used for that destination.
9.1.2. Destination Up ACK Signal 10.1.2. Destination Up Response Message
If the corresponding Destination Up signal contained the Credit Grant
data item, the Destination Up ACK signal MUST contain one of each of
the following data items:
o Credit Window Status (Section 9.2.2) If the corresponding Destination Up message contained the Credit
Grant data item, the Destination Up Response message MUST contain one
of each of the following data items:
9.1.3. Destination Update Signal o Credit Window Status (Section 10.2.2)
If the corresponding Destination Up signal contained the Credit Grant 10.1.3. Destination Update Message
data item, the Destination Update signal MUST contain one of each of
the following data items:
o Credit Window Status (Section 9.2.2) If the corresponding Destination Up message contained the Credit
Grant data item, the Destination Update message MUST contain one of
each of the following data items:
If the corresponding Destination Up signal contained the Credit Grant o Credit Window Status (Section 10.2.2)
data item, the Destination Update signal MAY contain one of each of If the corresponding Destination Up message contained the Credit
the following data items: Grant data item, the Destination Update message MAY contain one of
each of the following data items:
o Credit Grant (Section 9.2.1) o Credit Grant (Section 10.2.1)
o Credit Request (Section 9.2.3) o Credit Request (Section 10.2.3)
9.2. Credit-Windowing Data Items 10.2. Credit-Windowing Data Items
The credit-windowing extension introduces 3 additional data items. The credit-windowing extension introduces 3 additional data items.
If a peer has advertised during session initialization that it If a peer has advertised during session initialization that it
supports the credit-windowing extension then it MUST correctly supports the credit-windowing extension then it MUST correctly
process the following data items. process the following data items:
+------------+-----------------------+----------------+ +------------+------------------------------------------------------+
| Data Item | Description | Section | | Type Code | Description |
+------------+-----------------------+----------------+ +------------+------------------------------------------------------+
| TBD | Credit Grant | Section 9.2.1 | | 23 | Credit Grant (Section 10.2.1) |
| TBD | Credit Window Status | Section 9.2.2 | | 24 | Credit Window Status (Section 10.2.2) |
| TBD | Credit Request | Section 9.2.3 | | 25 | Credit Request (Section 10.2.3) |
+------------+-----------------------+----------------+ +------------+------------------------------------------------------+
9.2.1. Credit Grant 10.2.1. Credit Grant
The Credit Grant data item is sent from a DLEP participant to grant The Credit Grant data item is sent from a DLEP participant to grant
an increment to credits on a window. The Credit Grant data item MAY an increment to credits on a window. The Credit Grant data item MAY
appear in the Destination Up (Section 7.9) and Destination Update appear in the Destination Up (Section 8.9) and Destination Update
(Section 7.13) signals. The value in a Credit Grant data item (Section 8.13) messages. The value in a Credit Grant data item
represents an increment to be added to any existing credits available represents an increment to be added to any existing credits available
on the window. Upon successful receipt and processing of a Credit on the window. Upon successful receipt and processing of a Credit
Grant data item, the receiver MUST respond with a signal containing a Grant data item, the receiver MUST respond with a message containing
Credit Window Status data item to report the updated aggregate values a Credit Window Status data item to report the updated aggregate
for synchronization purposes, and if initializing a new credit values for synchronization purposes, and if initializing a new credit
window, granting initial credits. window, granting initial credits.
In the Destination Up signal, when credits are desired, the When DLEP peers desire to employ the credit-windowing extension, the
originating peer MUST set the initial credit value of the window it peer originating the Destination Up message MUST supply an initial,
controls (i.e., the Modem Receive Window, or Router Receive Window) non-zero value as the credit increment of the receive window it
to an initial, non-zero value. If the receiver of a Destination Up controls (i.e., the Modem Recive Window, or Router Receive Window).
signal with a Credit Grant data item supports credits, the receiver When receiving a Credit Grant data item on a Destination Up
MUST either reject the use of credits for this destination, via a (#msg_dest_up) message, the receiver MUST take one of the following
Destination Up ACK response containing a Status data item actions:
(Section 8.2) with a status code of 'Request Denied', or set the
initial value from the data contained in the Credit Window Status 1. Reject the use of credits for this destination, via the
data item. If the initialization completes successfully, the Destination Up Response message containing a Status data item
receiver MUST respond to the Destination Up signal with a Destination (Section 9.1) with a status code of 'Request Denied'. (See
Up ACK signal that contains a Credit Window Status data item, Table 3), or
initializing its receive window.
2. Initialize the appropriate window value of zero, then apply the
increment specified in the Credit Grant data item.
If the initialization completes successfully, the receiver MUST
respond to the Destination Up message with a Destination Up Response
message that contains a Credit Window Status data item, initializing
its receive window.
The Credit Grant data item contains the following fields: The Credit Grant data item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Credit Increment | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit Increment | | Credit Increment :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Credit Increment |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit Increment |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 8 Length: 8
Reserved: A 64-bit unsigned integer representing the additional Reserved: A 64-bit unsigned integer representing the additional
credits to be assigned to the credit window. credits to be assigned to the credit window.
Since credits can only be granted by the receiver on a window, the Since credits can only be granted by the receiver on a window, the
applicable credit window (either the MRW or the RRW) is derived from applicable credit window (either the MRW or the RRW) is derived from
the sender of the grant. The Credit Increment MUST NOT cause the the sender of the grant. The Credit Increment MUST NOT cause the
window to overflow; if this condition occurs, implementations MUST window to overflow; if this condition occurs, implementations MUST
set the credit window to the maximum value contained in a 64-bit set the credit window to the maximum value contained in a 64-bit
quantity. quantity.
9.2.2. Credit Window Status 10.2.2. Credit Window Status
If the credit-window extension is supported by the DLEP participants If the credit-window extension is supported by the DLEP participants
(both the router and the modem), the Credit Window Status data item (both the router and the modem), the Credit Window Status data item
MUST be sent by the participant receiving a Credit Grant for a given MUST be sent by the participant receiving a Credit Grant for a given
destination. destination.
The Credit Window Status data item contains the following fields: The Credit Window Status data item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Modem Receive Window Value | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Modem Receive Window Value | | Modem Receive Window Value :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Modem Receive Window Value | Router Receive Window Value | : Modem Receive Window Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Router Receive Window Value | | Router Receive Window Value :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Router Receive Window Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Router Receive Window Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 16 Length: 16
Modem Receive Window Value: A 64-bit unsigned integer, indicating Modem Receive Window Value: A 64-bit unsigned integer, indicating
the current number of credits available on the Modem Receive the current number of credits available on the Modem Receive
Window, for the destination referred to by the signal. Window, for the destination referred to by the message.
Router Receive Window Value: A 64-bit unsigned integer, indicating Router Receive Window Value: A 64-bit unsigned integer, indicating
the current number of credits available on the Router Receive the current number of credits available on the Router Receive
Window, for the destination referred to by the signal. Window, for the destination referred to by the message.
9.2.3. Credit Request 10.2.3. Credit Request
The Credit Request data item MAY be sent from either DLEP The Credit Request data item MAY be sent from either DLEP
participant, via the Destination Update signal (Section 7.13), to participant, via the Destination Update message (Section 8.13), to
indicate the desire for the partner to grant additional credits in indicate the desire for the partner to grant additional credits in
order for data transfer to proceed on the session. If the order for data transfer to proceed on the session. If the
corresponding Destination Up signal (Section 7.9) for this session corresponding Destination Up message (Section 8.9) for this session
did NOT contain a Credit Window Status data item, indicating that did not contain a Credit Window Status data item, indicating that
credits are to be used on the session, then the Credit Request data credits are to be used on the session, then the Credit Request data
item MUST be silently dropped by the receiver. item MUST be silently dropped by the receiver.
The Credit Request data item contains the following fields: The Credit Request data item contains the following fields:
0 1 2 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type| Length | Reserved, MUST| | Data Item Type | Length |
| | | be set to 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBD Data Item Type: TBD
Length: 1 Length: 0
Reserved: This field is currently unused and MUST be set to 0. 11. Security Considerations
10. Security Considerations The potential security concerns when using DLEP are:
The protocol does not contain any mechanisms for security (e.g., 1. DLEP peers may be 'spoofed' by an attacker, either at DLEP
authentication or encryption). The protocol assumes that any session initialization, or by injection of messages once a
security would be implemented in the underlying transport (for session has been established, and/or
example, by use of TLS or some other mechanism), and is therefore
outside the scope of this document.
11. IANA Considerations 2. DLEP data items could be altered by an attacker, causing the
receiving peer to inappropriately alter its information base
concerning network status.
The protocol itself does not contain any mechanisms for security
(e.g., authentication or encryption), as it assumes that an
appropriate level of authentication and non-repudiation is acheived
by use of [TLS] when necessary. This specification does not address
security of the data plane, as it (the data plane) is not affected,
and standard security procedures can be employed.
12. IANA Considerations
This section specifies requests to IANA. This section specifies requests to IANA.
11.1. Registrations 12.1. Registrations
This specification defines: This specification defines:
o A new repository for DLEP signals, with sixteen values currently o A new repository for DLEP signals and messages, with sixteen (16)
assigned. values currently assigned.
o Reservation of numbering space for Experimental DLEP signals. o Reservation of a Private Use numbering space for experimental DLEP
signals and messages.
o A new repository for DLEP data items, with twenty-six values o A new repository for DLEP data items, with twenty-four (24) values
currently assigned. currently assigned.
o Reservation of numbering space in the data items repository for o Reservation of a Private Use numbering space in the data items
experimental data items. repository for experimental data items.
o A new repository for DLEP status codes, with seven currently o A new repository for DLEP status codes, with eight (8) currently
assigned. assigned.
o A new repository for DLEP extensions, with one value currently o Reservation of a Private Use numbering space in the status codes
repository for experimental status codes.
o A new repository for DLEP extensions, with one (1) value currently
assigned. assigned.
o Reservation of a Private Use numbering space in the extension
repository for experimental extensions.
o A request for allocation of a well-known port for DLEP TCP and UDP o A request for allocation of a well-known port for DLEP TCP and UDP
communication. communication.
o A request for allocation of a multicast IP address for DLEP o A request for allocation of a multicast IP address for DLEP
discovery. discovery.
11.2. Expert Review: Evaluation Guidelines 12.2. Expert Review: Evaluation Guidelines
No additional guidelines for expert review are anticipated. No additional guidelines for expert review are anticipated.
11.3. Signal Type Registration 12.3. Signal/Message Type Registration
A new repository must be created with the values of the DLEP signals.
All signal values are in the range [0..255].
Valid signals are:
o Peer Discovery
o Peer Offer
o Peer Initialization
o Peer Initialization ACK
o Peer Update
o Peer Update ACK
o Peer Termination
o Peer Termination ACK
o Destination Up
o Destination Up ACK
o Destination Down
o Destination Down ACK
o Destination Update
o Heartbeat
o Link Characteristics Request
o Link Characteristics ACK A new repository must be created with the values of the DLEP signals
and messages.
It is also requested that the repository contain space for All signal and message values are in the range [0..65535], defined in
experimental signal types. Table 1.
11.4. DLEP Data Item Registrations 12.4. DLEP Data Item Registrations
A new repository for DLEP data items must be created. A new repository for DLEP data items must be created.
All data item values are in the range [0..255]. All data item values are in the range [0..65535], defined in Table 2.
Valid data items are:
o DLEP Version
o Status
o IPv4 Connection Point
o IPv6 Connection Point
o Peer Type
o Heartbeat Interval
o Extensions Supported
o Experimental Definition
o MAC Address
o IPv4 Address
o IPv6 Address
o IPv4 Attached Subnet
o IPv6 Attached Subnet
o Maximum Data Rate (Receive)
o Maximum Data Rate (Transmit)
o Current Data Rate (Receive)
o Current Data Rate (Transmit)
o Latency
o Resources (Receive)
o Resources (Transmit)
o Relative Link Quality (Receive)
o Relative Link Quality (Transmit)
o Link Characteristics ACK Timer
o Credit Window Status
o Credit Grant
o Credit Request
It is also requested that the registry allocation contain space for
experimental data items.
11.5. DLEP Status Code Registrations 12.5. DLEP Status Code Registrations
A new repository for DLEP status codes must be created. A new repository for DLEP status codes must be created.
All status codes are in the range [0..255]. All status codes are in the range [0..255], defined in Table 3.
Valid status codes are:
o Success (value 0)
o Unknown Signal
o Invalid Data
o Unexpected Signal
o Request Denied
o Timed Out
o Invalid Destination
11.6. DLEP Extensions Registrations 12.6. DLEP Extensions Registrations
A new repository for DLEP extensions must be created. A new repository for DLEP extensions must be created.
All extension values are in the range [0..255]. All extension values are in the range [0..65535]. Current
allocations are:
Valid extensions are: +-------------+-----------------------------------------------------+
| Code | Description |
+-------------+-----------------------------------------------------+
| 0 | Reserved |
| 1 | Credit Windowing (Section 10) |
| 2-65519 | Reserved for future extensions |
| 65520-65534 | Private Use. Available for experiments |
| 65535 | Reserved |
+-------------+-----------------------------------------------------+
o DLEP_EXT_CREDITS - Credit windowing Table 4: DLEP Extension types
11.7. DLEP Well-known Port 12.7. DLEP Well-known Port
It is requested that IANA allocate a well-known port number for DLEP It is requested that IANA allocate a well-known port number for DLEP
communication. communication.
11.8. DLEP Multicast Address 12.8. DLEP Multicast Address
It is requested that IANA allocate a multicast address for DLEP It is requested that IANA allocate a multicast address for DLEP
discovery signals. discovery signals.
12. Acknowledgements 13. Acknowledgements
We would like to acknowledge and thank the members of the DLEP design We would like to acknowledge and thank the members of the DLEP design
team, who have provided invaluable insight. The members of the team, who have provided invaluable insight. The members of the
design team are: Teco Boot, Bow-Nan Cheng, John Dowdell, and Henning design team are: Teco Boot, Bow-Nan Cheng, John Dowdell, and Henning
Rogge. Rogge.
We would also like to acknowledge the influence and contributions of We would also like to acknowledge the influence and contributions of
Greg Harrison, Chris Olsen, Martin Duke, Subir Das, Jaewon Kang, Greg Harrison, Chris Olsen, Martin Duke, Subir Das, Jaewon Kang,
Vikram Kaul, Nelson Powell and Victoria Mercieca. Vikram Kaul, Nelson Powell and Victoria Mercieca.
13. References 14. References
13.1. Normative References 14.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
13.2. Informative References 14.2. Informative References
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008. (TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC5578] Berry, B., Ratliff, S., Paradise, E., Kaiser, T., and M. [RFC5578] Berry, B., Ratliff, S., Paradise, E., Kaiser, T., and M.
Adams, "PPP over Ethernet (PPPoE) Extensions for Credit Adams, "PPP over Ethernet (PPPoE) Extensions for Credit
Flow and Link Metrics", RFC 5578, February 2010. Flow and Link Metrics", RFC 5578, February 2010.
Appendix A. Peer Level Signal Flows Appendix A. Discovery Signal Flows
A.1. Discovery
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
| Router initiates discovery, starts | Router initiates discovery, starts
| a timer, send Peer Discovery | a timer, send Peer Discovery
|-------Peer Discovery---->|| signal. |-------Peer Discovery---->|| signal.
~ ~ ~ ~ ~ ~ ~ Router discovery timer expires ~ ~ ~ ~ ~ ~ ~ Router discovery timer expires
without receiving Peer Offer. without receiving Peer Offer.
skipping to change at page 58, line 27 skipping to change at page 58, line 30
| Modem receives Peer Discovery | Modem receives Peer Discovery
| signal. | signal.
| |
| Modem sends Peer Offer with | Modem sends Peer Offer with
|<--------Peer Offer-------------| Connection Point information. |<--------Peer Offer-------------| Connection Point information.
: :
: Router MAY cancel discovery timer : Router MAY cancel discovery timer
: and stop sending Peer Discovery : and stop sending Peer Discovery
: signals. : signals.
A.2. Session Initialization Appendix B. Peer Level Message Flows
B.1. Session Initialization
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
| Router connects to discovered or | Router connects to discovered or
| pre-configured Modem Connection | pre-configured Modem Connection
|---------TCP connect----------> Point. |---------TCP connect----------> Point.
| |
| Router sends Peer Initialization | Router sends Session Initialization
|-------Peer Initialization----->| signal. |----Session Initialization----->| message.
| |
| Modem receives Peer Initialization | Modem receives Session Initialization
| signal. | message.
| |
| Modem sends Peer Initialization | Modem sends Session Initialization
| ACK, with compatible extensions, |<--Session Initialization Resp.-| Response, with Success status data item.
|<----Peer Initialization ACK----| and Success status data item.
| | | |
|<<============================>>| Session established. Heartbeats |<<============================>>| Session established. Heartbeats
: : begin. : : begin.
A.3. Session Initialization - Refused B.2. Session Initialization - Refused
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
| Router connects to discovered or | Router connects to discovered or
| pre-configured Modem Connection | pre-configured Modem Connection
|---------TCP connect----------> Point. |---------TCP connect----------> Point.
| |
| Router sends Peer Initialization | Router sends Session Initialization
|-------Peer Initialization----->| signal. |-----Session Initialization---->| message.
| |
| Modem receives Peer Initialization | Modem receives Session Initialization
| signal, and will not support the | message, and will not support the
| advertised version, experiment or | advertised extensions.
| extensions.
| |
| Modem sends Peer Initialization | Modem sends Session Initialization
| ACK, with 'Request Denied' status | Response, with 'Request Denied' status
|<----Peer Initialization ACK----| data item. |<-Session Initialization Resp.--| data item.
| |
| <---- TCP shutdown (send)-----| Modem closes TCP connection.
| |
| Router receives negative Peer
| Initialization ACK, closes
|---------TCP close-----------> TCP connection.
| |
||------------------------------|| Session not started. | Router receives negative Session
| Initialization Response, closes
||---------TCP close------------|| TCP connection.
A.4. Router Changes IP Addresses B.3. Router Changes IP Addresses
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
| Router sends Peer Update signal to | Router sends Session Update message to
|--------Peer Update------------>| announce change of IP address |-------Session Update---------->| announce change of IP address
| |
| Modem receives Peer Update signal | Modem receives Session Update message
| and updates internal state. | and updates internal state.
| |
|<-------Peer Update ACK---------| Modem sends Peer Update ACK. |<----Session Update Response----| Modem sends Session Update Response.
A.5. Modem Changes Session-wide Metrics B.4. Modem Changes Session-wide Metrics
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
| Modem sends Peer Update signal to | Modem sends Session Update message to
| announce change of modem-wide | announce change of modem-wide
|<--------Peer Update------------| metrics |<--------Session Update---------| metrics
| |
| Router receives Peer Update signal | Router receives Session Update message
| and updates internal state. | and updates internal state.
| |
|-------Peer Update ACK--------->| Router sends Peer Update ACK. |----Session Update Response---->| Router sends Session Update Response.
A.6. Router Terminates Session B.5. Router Terminates Session
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
| Router sends Peer Termination | Router sends Session Termination
|-------Peer Termination-------->| signal with Status data item. |------Session Termination------>| message with Status data item.
| | | |
|-------TCP shutdown (send)---> | Router stops sending signals. |-------TCP shutdown (send)---> | Router stops sending messages.
| |
| Modem receives Peer Termination, | Modem receives Session Termination,
| stops counting received heartbeats | stops counting received heartbeats
| and stops sending heartbeats. | and stops sending heartbeats.
| |
| Modem sends Peer Termination ACK | Modem sends Session Termination Response
|<-----Peer Termination ACK------| with Status 'Success'. |<---Session Termination Resp.---| with Status 'Success'.
| |
| <----TCP shutdown (send)------| Modem stops sending signals.
| |
||------------------------------|| Session terminated. | Modem stops sending messages.
|
||---------TCP close------------|| Session terminated.
A.7. Modem Terminates Session B.6. Modem Terminates Session
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
| Modem sends Peer Termination | Modem sends Session Termination
|<------Peer Termination---------| signal with Status data item. |<----Session Termination--------| message with Status data item.
| |
| <----TCP shutdown (send)------| Modem stops sending signals.
| |
| Router receives Peer Termination, | Modem stops sending messages.
|
| Router receives Session Termination,
| stops counting received heartbeats | stops counting received heartbeats
| and stops sending heartbeats. | and stops sending heartbeats.
| |
| Router sends Peer Termination ACK | Router sends Session Termination Response
|------Peer Termination ACK----->| with Status 'Success'. |---Session Termination Resp.--->| with Status 'Success'.
| |
|-------TCP shutdown (send)---> | Router stops sending signals.
| |
||------------------------------|| Session terminated. | Router stops sending messages.
|
||---------TCP close------------|| Session terminated.
A.8. Session Heartbeats B.7. Session Heartbeats
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
|----------Heartbeat------------>| Router sends heartbeat signal |----------Heartbeat------------>| Router sends heartbeat message
| |
| Modem resets heartbeats missed | Modem resets heartbeats missed
| counter. | counter.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|----------[Any signal]--------->| When the Modem receives any signal |---------[Any message]--------->| When the Modem receives any message
| from the Router. | from the Router.
| |
| Modem resets heartbeats missed | Modem resets heartbeats missed
| counter. | counter.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|<---------Heartbeat-------------| Modem sends heartbeat signal |<---------Heartbeat-------------| Modem sends heartbeat message
| |
| Router resets heartbeats missed | Router resets heartbeats missed
| counter. | counter.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|<---------[Any signal]----------| When the Router receives any |<--------[Any message]----------| When the Router receives any
| signal from the Modem. | message from the Modem.
| |
| Modem resets heartbeats missed | Modem resets heartbeats missed
| counter. | counter.
A.9. Router Detects a Heartbeat timeout B.8. Router Detects a Heartbeat timeout
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
||<----------------------| Router misses a heartbeat ||<----------------------| Router misses a heartbeat
| ||<----------------------| Router misses too many heartbeats | ||<----------------------| Router misses too many heartbeats
| |
| |
|-------Peer Termination-------->| Router sends Peer Termination |------Session Termination------>| Router sends Session Termination
| signal with 'Timeout' Status | message with 'Timeout' Status
| data item. | data item.
: :
: Termination proceeds as above. : Termination proceeds as above.
A.10. Modem Detects a Heartbeat timeout B.9. Modem Detects a Heartbeat timeout
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
|---------------------->|| Modem misses a heartbeat |---------------------->|| Modem misses a heartbeat
|---------------------->|| | Modem misses too many heartbeats |---------------------->|| | Modem misses too many heartbeats
| |
| |
|<-------Peer Termination--------| Modem sends Peer Termination |<-----Session Termination-------| Modem sends Session Termination
| signal with 'Timeout' Status | message with 'Timeout' Status
| data item. | data item.
: :
: Termination proceeds as above. : Termination proceeds as above.
Appendix B. Destination Specific Signal Flows Appendix C. Destination Specific Signal Flows
B.1. Common Destination Signaling C.1. Common Destination Signaling
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
| Modem detects a new logical | Modem detects a new logical
| destination is reachable, and | destination is reachable, and
|<-------Destination Up----------| sends Destination Up signal. |<-------Destination Up----------| sends Destination Up message.
| |
|--------Destination Up ACK----->| Router sends Destination Up ACK. |------Destination Up Resp.----->| Router sends Destination Up Response.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects change in logical | Modem detects change in logical
| destination metrics, and sends | destination metrics, and sends
|<-------Destination Update------| Destination Update signal. |<-------Destination Update------| Destination Update message.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects change in logical | Modem detects change in logical
| destination metrics, and sends | destination metrics, and sends
|<-------Destination Update------| Destination Update signal. |<-------Destination Update------| Destination Update message.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects logical destination | Modem detects logical destination
| is no longer reachable, and sends | is no longer reachable, and sends
|<-------Destination Down--------| Destination Down signal. |<-------Destination Down--------| Destination Down message.
| |
| Router receives Destination Down, | Router receives Destination Down,
| updates internal state, and sends | updates internal state, and sends
|--------Destination Down ACK--->| Destination Down ACK signal. |------Destination Down Resp.--->| Destination Down Response message.
B.2. Multicast Destination Signaling C.2. Multicast Destination Signaling
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
| Router detects a new multicast | Router detects a new multicast
| destination is in use, and sends | destination is in use, and sends
|--------Destination Up--------->| Destination Up signal. |--------Destination Up--------->| Destination Up message.
| |
| Modem updates internal state to | Modem updates internal state to
| monitor multicast destination, and | monitor multicast destination, and
|<-------Destination Up ACK------| sends Destination Up ACK. |<-----Destination Up Resp.------| sends Destination Up Response.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects change in multicast | Modem detects change in multicast
| destination metrics, and sends | destination metrics, and sends
|<-------Destination Update------| Destination Update signal. |<-------Destination Update------| Destination Update message.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects change in multicast | Modem detects change in multicast
| destination metrics, and sends | destination metrics, and sends
|<-------Destination Update------| Destination Update signal. |<-------Destination Update------| Destination Update message.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Router detects multicast | Router detects multicast
| destination is no longer in use, | destination is no longer in use,
|--------Destination Down------->| and sends Destination Down signal. |--------Destination Down------->| and sends Destination Down message.
| |
| Modem receives Destination Down, | Modem receives Destination Down,
| updates internal state, and sends | updates internal state, and sends
|<-------Destination Down ACK----| Destination Down ACK signal. |<-----Destination Down Resp.----| Destination Down Response message.
B.3. Link Characteristics Request C.3. Link Characteristics Request
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
Destination has already been Destination has already been
~ ~ ~ ~ ~ ~ ~ announced by either peer. ~ ~ ~ ~ ~ ~ ~ announced by either peer.
| Router requires different | Router requires different
| Characteristics for the | Characteristics for the
| destination, and sends Link | destination, and sends Link
|--Link Characteristics Request->| Characteristics Request signal. |--Link Characteristics Request->| Characteristics Request message.
| |
| Modem attempts to adjust link | Modem attempts to adjust link
| status to meet the received | status to meet the received
| request, and sends a Link | request, and sends a Link
| Characteristics Request ACK | Characteristics Response
|<---Link Char. Request ACK------| signal with the new values. |<---Link Characteristics Resp.--| message with the new values.
Authors' Addresses Authors' Addresses
Stan Ratliff Stan Ratliff
VT iDirect VT iDirect
13861 Sunrise Valley Drive, Suite 300 13861 Sunrise Valley Drive, Suite 300
Herndon, VA 20171 Herndon, VA 20171
USA USA
Email: sratliff@idirect.net Email: sratliff@idirect.net
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