< draft-ietf-manet-dlep-22.txt   draft-ietf-manet-dlep-23.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 S. Jury
Expires: October 9, 2016 Expires: January 19, 2017 Cisco Systems
S. Jury
Cisco Systems
D. Satterwhite D. Satterwhite
Broadcom Broadcom
R. Taylor R. Taylor
Airbus Defence & Space Airbus Defence & Space
April 7, 2016 B. Berry
July 18, 2016
Dynamic Link Exchange Protocol (DLEP) Dynamic Link Exchange Protocol (DLEP)
draft-ietf-manet-dlep-22 draft-ietf-manet-dlep-23
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-
skipping to change at page 1, line 45 skipping to change at page 1, line 44
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This Internet-Draft will expire on October 9, 2016. This Internet-Draft will expire on January 19, 2017.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . 7
2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 7 2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 7
2.1. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 9 2.1. Destinations . . . . . . . . . . . . . . . . . . . . . . 7
3. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . 8
4. DLEP Session Flow . . . . . . . . . . . . . . . . . . . . . . 10 3.1. Requirements . . . . . . . . . . . . . . . . . . . . . . 8
4.1. Peer Discovery State . . . . . . . . . . . . . . . . . . 11 4. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.2. Session Initialization State . . . . . . . . . . . . . . 12 5. DLEP Session Flow . . . . . . . . . . . . . . . . . . . . . . 11
4.3. In-Session State . . . . . . . . . . . . . . . . . . . . 12 5.1. Peer Discovery State . . . . . . . . . . . . . . . . . . 11
4.3.1. Heartbeats . . . . . . . . . . . . . . . . . . . . . 13 5.2. Session Initialization State . . . . . . . . . . . . . . 12
4.4. Session Termination State . . . . . . . . . . . . . . . . 13 5.3. In-Session State . . . . . . . . . . . . . . . . . . . . 12
4.5. Session Reset state . . . . . . . . . . . . . . . . . . . 14 5.3.1. Heartbeats . . . . . . . . . . . . . . . . . . . . . 13
4.5.1. Unexpected TCP connection termination . . . . . . . . 14 5.4. Session Termination State . . . . . . . . . . . . . . . . 13
5. Transaction Model . . . . . . . . . . . . . . . . . . . . . . 14 5.5. Session Reset state . . . . . . . . . . . . . . . . . . . 14
6. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . 15 5.5.1. Unexpected TCP connection termination . . . . . . . . 14
6.1. Experiments . . . . . . . . . . . . . . . . . . . . . . . 15 6. Transaction Model . . . . . . . . . . . . . . . . . . . . . . 14
7. Scalability . . . . . . . . . . . . . . . . . . . . . . . . . 16 7. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . 15
8. DLEP Signal and Message Structure . . . . . . . . . . . . . . 16 7.1. Experiments . . . . . . . . . . . . . . . . . . . . . . . 15
8.1. DLEP Signal Header . . . . . . . . . . . . . . . . . . . 17 8. Scalability . . . . . . . . . . . . . . . . . . . . . . . . . 16
8.2. DLEP Message Header . . . . . . . . . . . . . . . . . . . 17 9. DLEP Signal and Message Structure . . . . . . . . . . . . . . 16
8.3. DLEP Generic Data Item . . . . . . . . . . . . . . . . . 18 9.1. DLEP Signal Header . . . . . . . . . . . . . . . . . . . 17
9. DLEP Signals and Messages . . . . . . . . . . . . . . . . . . 19 9.2. DLEP Message Header . . . . . . . . . . . . . . . . . . . 17
9.1. General Processing Rules . . . . . . . . . . . . . . . . 20 9.3. DLEP Generic Data Item . . . . . . . . . . . . . . . . . 18
9.2. Status code processing . . . . . . . . . . . . . . . . . 21 10. DLEP Signals and Messages . . . . . . . . . . . . . . . . . . 18
9.3. Peer Discovery Signal . . . . . . . . . . . . . . . . . . 21 10.1. General Processing Rules . . . . . . . . . . . . . . . . 19
9.4. Peer Offer Signal . . . . . . . . . . . . . . . . . . . . 22 10.2. Status code processing . . . . . . . . . . . . . . . . . 20
9.5. Session Initialization Message . . . . . . . . . . . . . 22 10.3. Peer Discovery Signal . . . . . . . . . . . . . . . . . 20
9.6. Session Initialization Response Message . . . . . . . . . 23 10.4. Peer Offer Signal . . . . . . . . . . . . . . . . . . . 20
9.7. Session Update Message . . . . . . . . . . . . . . . . . 25 10.5. Session Initialization Message . . . . . . . . . . . . . 21
9.8. Session Update Response Message . . . . . . . . . . . . . 26 10.6. Session Initialization Response Message . . . . . . . . 22
9.9. Session Termination Message . . . . . . . . . . . . . . . 26 10.7. Session Update Message . . . . . . . . . . . . . . . . . 23
9.10. Session Termination Response Message . . . . . . . . . . 27 10.8. Session Update Response Message . . . . . . . . . . . . 25
9.11. Destination Up Message . . . . . . . . . . . . . . . . . 27 10.9. Session Termination Message . . . . . . . . . . . . . . 25
9.12. Destination Up Response Message . . . . . . . . . . . . . 28 10.10. Session Termination Response Message . . . . . . . . . . 25
9.13. Destination Announce Message . . . . . . . . . . . . . . 29 10.11. Destination Up Message . . . . . . . . . . . . . . . . . 26
9.14. Destination Announce Response Message . . . . . . . . . . 29 10.12. Destination Up Response Message . . . . . . . . . . . . 27
9.15. Destination Down Message . . . . . . . . . . . . . . . . 31 10.13. Destination Announce Message . . . . . . . . . . . . . . 27
9.16. Destination Down Response Message . . . . . . . . . . . . 31 10.14. Destination Announce Response Message . . . . . . . . . 28
9.17. Destination Update Message . . . . . . . . . . . . . . . 31 10.15. Destination Down Message . . . . . . . . . . . . . . . . 30
9.18. Link Characteristics Request Message . . . . . . . . . . 33 10.16. Destination Down Response Message . . . . . . . . . . . 30
9.19. Link Characteristics Response Message . . . . . . . . . . 33 10.17. Destination Update Message . . . . . . . . . . . . . . . 30
9.20. Heartbeat Message . . . . . . . . . . . . . . . . . . . . 34 10.18. Link Characteristics Request Message . . . . . . . . . . 32
10. DLEP Data Items . . . . . . . . . . . . . . . . . . . . . . . 35 10.19. Link Characteristics Response Message . . . . . . . . . 32
10.1. Status . . . . . . . . . . . . . . . . . . . . . . . . . 36 10.20. Heartbeat Message . . . . . . . . . . . . . . . . . . . 33
10.2. IPv4 Connection Point . . . . . . . . . . . . . . . . . 38 11. DLEP Data Items . . . . . . . . . . . . . . . . . . . . . . . 34
10.3. IPv6 Connection Point . . . . . . . . . . . . . . . . . 39 11.1. Status . . . . . . . . . . . . . . . . . . . . . . . . . 35
10.4. Peer Type . . . . . . . . . . . . . . . . . . . . . . . 40 11.2. IPv4 Connection Point . . . . . . . . . . . . . . . . . 37
10.5. Heartbeat Interval . . . . . . . . . . . . . . . . . . . 40 11.3. IPv6 Connection Point . . . . . . . . . . . . . . . . . 37
10.6. Extensions Supported . . . . . . . . . . . . . . . . . . 41 11.4. Peer Type . . . . . . . . . . . . . . . . . . . . . . . 39
10.7. MAC Address . . . . . . . . . . . . . . . . . . . . . . 41 11.5. Heartbeat Interval . . . . . . . . . . . . . . . . . . . 39
10.8. IPv4 Address . . . . . . . . . . . . . . . . . . . . . . 42 11.6. Extensions Supported . . . . . . . . . . . . . . . . . . 40
10.9. IPv6 Address . . . . . . . . . . . . . . . . . . . . . . 43 11.7. MAC Address . . . . . . . . . . . . . . . . . . . . . . 40
10.10. IPv4 Attached Subnet . . . . . . . . . . . . . . . . . . 44 11.8. IPv4 Address . . . . . . . . . . . . . . . . . . . . . . 41
10.11. IPv6 Attached Subnet . . . . . . . . . . . . . . . . . . 45 11.9. IPv6 Address . . . . . . . . . . . . . . . . . . . . . . 42
10.12. Maximum Data Rate (Receive) . . . . . . . . . . . . . . 46 11.10. IPv4 Attached Subnet . . . . . . . . . . . . . . . . . . 43
10.13. Maximum Data Rate (Transmit) . . . . . . . . . . . . . . 46 11.11. IPv6 Attached Subnet . . . . . . . . . . . . . . . . . . 44
10.14. Current Data Rate (Receive) . . . . . . . . . . . . . . 47 11.12. Maximum Data Rate (Receive) . . . . . . . . . . . . . . 45
10.15. Current Data Rate (Transmit) . . . . . . . . . . . . . . 48 11.13. Maximum Data Rate (Transmit) . . . . . . . . . . . . . . 45
10.16. Latency . . . . . . . . . . . . . . . . . . . . . . . . 48 11.14. Current Data Rate (Receive) . . . . . . . . . . . . . . 46
10.17. Resources . . . . . . . . . . . . . . . . . . . . . . . 49 11.15. Current Data Rate (Transmit) . . . . . . . . . . . . . . 47
10.18. Relative Link Quality (Receive) . . . . . . . . . . . . 50 11.16. Latency . . . . . . . . . . . . . . . . . . . . . . . . 48
10.19. Relative Link Quality (Transmit) . . . . . . . . . . . . 51 11.17. Resources . . . . . . . . . . . . . . . . . . . . . . . 48
10.20. Maximum Transmission Unit (MTU) . . . . . . . . . . . . 52 11.18. Relative Link Quality (Receive) . . . . . . . . . . . . 49
11. Security Considerations . . . . . . . . . . . . . . . . . . . 52 11.19. Relative Link Quality (Transmit) . . . . . . . . . . . . 50
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 53 11.20. Maximum Transmission Unit (MTU) . . . . . . . . . . . . 50
12.1. Registrations . . . . . . . . . . . . . . . . . . . . . 53 12. Security Considerations . . . . . . . . . . . . . . . . . . . 51
12.2. Signal Type Registration . . . . . . . . . . . . . . . . 53 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 52
12.3. Message Type Registration . . . . . . . . . . . . . . . 53 13.1. Registrations . . . . . . . . . . . . . . . . . . . . . 52
12.4. DLEP Data Item Registrations . . . . . . . . . . . . . . 54 13.2. Signal Type Registration . . . . . . . . . . . . . . . . 52
12.5. DLEP Status Code Registrations . . . . . . . . . . . . . 55 13.3. Message Type Registration . . . . . . . . . . . . . . . 52
12.6. DLEP Extensions Registrations . . . . . . . . . . . . . 56 13.4. DLEP Data Item Registrations . . . . . . . . . . . . . . 53
12.7. DLEP Well-known Port . . . . . . . . . . . . . . . . . . 56 13.5. DLEP Status Code Registrations . . . . . . . . . . . . . 54
12.8. DLEP IPv4 Link-local Multicast Address . . . . . . . . . 57 13.6. DLEP Extensions Registrations . . . . . . . . . . . . . 55
12.9. DLEP IPv6 Link-local Multicast Address . . . . . . . . . 57 13.7. DLEP Well-known Port . . . . . . . . . . . . . . . . . . 55
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 57 13.8. DLEP IPv4 Link-local Multicast Address . . . . . . . . . 55
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 57 13.9. DLEP IPv6 Link-local Multicast Address . . . . . . . . . 55
14.1. Normative References . . . . . . . . . . . . . . . . . . 57 14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 55
14.2. Informative References . . . . . . . . . . . . . . . . . 57 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 56
Appendix A. Discovery Signal Flows . . . . . . . . . . . . . . . 58 15.1. Normative References . . . . . . . . . . . . . . . . . . 56
Appendix B. Peer Level Message Flows . . . . . . . . . . . . . . 58 15.2. Informative References . . . . . . . . . . . . . . . . . 56
B.1. Session Initialization . . . . . . . . . . . . . . . . . 58 Appendix A. Discovery Signal Flows . . . . . . . . . . . . . . . 57
B.2. Session Initialization - Refused . . . . . . . . . . . . 59 Appendix B. Peer Level Message Flows . . . . . . . . . . . . . . 57
B.3. Router Changes IP Addresses . . . . . . . . . . . . . . . 60 B.1. Session Initialization . . . . . . . . . . . . . . . . . 57
B.4. Modem Changes Session-wide Metrics . . . . . . . . . . . 60 B.2. Session Initialization - Refused . . . . . . . . . . . . 58
B.5. Router Terminates Session . . . . . . . . . . . . . . . . 60 B.3. Router Changes IP Addresses . . . . . . . . . . . . . . . 58
B.6. Modem Terminates Session . . . . . . . . . . . . . . . . 61 B.4. Modem Changes Session-wide Metrics . . . . . . . . . . . 58
B.7. Session Heartbeats . . . . . . . . . . . . . . . . . . . 61 B.5. Router Terminates Session . . . . . . . . . . . . . . . . 59
B.8. Router Detects a Heartbeat timeout . . . . . . . . . . . 62 B.6. Modem Terminates Session . . . . . . . . . . . . . . . . 59
B.9. Modem Detects a Heartbeat timeout . . . . . . . . . . . . 63 B.7. Session Heartbeats . . . . . . . . . . . . . . . . . . . 60
Appendix C. Destination Specific Message Flows . . . . . . . . . 63 B.8. Router Detects a Heartbeat timeout . . . . . . . . . . . 60
C.1. Common Destination Notification . . . . . . . . . . . . . 63 B.9. Modem Detects a Heartbeat timeout . . . . . . . . . . . . 61
C.2. Multicast Destination Notification . . . . . . . . . . . 64 Appendix C. Destination Specific Message Flows . . . . . . . . . 61
C.3. Link Characteristics Request . . . . . . . . . . . . . . 65 C.1. Common Destination Notification . . . . . . . . . . . . . 61
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 66 C.2. Multicast Destination Notification . . . . . . . . . . . 62
C.3. Link Characteristics Request . . . . . . . . . . . . . . 63
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 63
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 broadband modems. Fluctuations in speed and quality of these and broadband 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,
rain fade, etc. It is also quite possible that link quality and rain fade, etc. It is also quite possible that link quality and
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Another complicating factor for mobile networks are the different Another complicating factor for mobile networks are the different
methods of physically connecting the modem devices to the router. methods of physically connecting the modem devices to the router.
Modems can be deployed as an interface card in a router's chassis, or Modems can be deployed as an interface card in a router's chassis, or
as a standalone device connected to the router via Ethernet or serial as a standalone device connected to the router via Ethernet or serial
link. In the case of Ethernet attachment, with existing protocols link. In the case of Ethernet attachment, with existing protocols
and techniques, routing software cannot be aware of convergence and techniques, routing software cannot be aware of convergence
events occurring on the radio link (e.g., acquisition or loss of a events occurring on the radio link (e.g., acquisition or loss of a
potential routing neighbor), nor can the router be aware of the potential routing neighbor), nor can the router be aware of the
actual capacity of the link. This lack of awareness, along with the actual capacity of the link. This lack of awareness, along with the
variability in datarate, leads to a situation where finding the variability in datarate, leads to a situation where finding the
(current) best route through the network to a given destination is (current) best route through the network to a given node is difficult
difficult to establish and properly maintain. This is especially to establish and properly maintain. This is especially true of
true of demand-based access schemes such as Demand Assigned Multiple demand-based access schemes such as Demand Assigned Multiple Access
Access (DAMA) implementations used on some satellite systems. With a (DAMA) implementations used on some satellite systems. With a DAMA-
DAMA-based system, additional datarate may be available, but will not based system, additional datarate may be available, but will not be
be used unless the network devices emit traffic at a rate higher than used unless the network devices emit traffic at a rate higher than
the currently established rate. Increasing the traffic rate does not the currently established rate. Increasing the traffic rate does not
guarantee additional datarate will be allocated; rather, it may guarantee additional datarate will be allocated; rather, it may
result in data loss and additional retransmissions on the link. result in data loss and additional retransmissions on the link.
Addressing the challenges listed above, the co-authors have developed Addressing the challenges listed above, the Dynamic Link Exchange
the Dynamic Link Exchange Protocol, or DLEP. The DLEP protocol runs Protocol, or DLEP, has been developed. The DLEP protocol runs
between a router and its attached modem devices, allowing the modem between a router and its attached modem devices, allowing the modem
to communicate link characteristics as they change, and convergence to communicate link characteristics as they change, and convergence
events (acquisition and loss of potential routing destinations). The events (acquisition and loss of potential routing next-hops). The
following diagrams are used to illustrate the scope of DLEP packets. following diagrams are used to illustrate the scope of DLEP packets.
|-------Local Node-------| |-------Remote Node------| |-------Local Node-------| |-------Remote Node------|
| | | | | | | |
+--------+ +-------+ +-------+ +--------+ +--------+ +-------+ +-------+ +--------+
| Router |=======| Modem |{~~~~~~~~}| Modem |=======| Router | | Router |=======| Modem |{~~~~~~~~}| Modem |=======| Router |
| | | Device| | Device| | | | | | Device| | Device| | |
+--------+ +-------+ +-------+ +--------+ +--------+ +-------+ +-------+ +--------+
| | | Link | | | | | | Link | | |
|-DLEP--| | Protocol | |-DLEP--| |-DLEP--| | Protocol | |-DLEP--|
skipping to change at page 7, line 37 skipping to change at page 7, line 12
+---+----+ +---+----+
| |
| |
+---+----+ +---+----+
| Router | | Router |
| | | |
+--------+ +--------+
Figure 2: DLEP Network with Multiple Modem Devices Figure 2: DLEP Network with Multiple Modem Devices
1.1. Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14, RFC 2119 [RFC2119].
2. Protocol Overview 2. Protocol Overview
DLEP defines a set of Messages used by modems and their attached DLEP defines a set of Messages used by modems and their attached
routers to communicate events that occur on the physical link(s) routers to communicate events that occur on the physical link(s)
managed by the modem: for example, a remote node entering or leaving managed by the modem: for example, a remote node entering or leaving
the network, or that the link has changed. Associated with these the network, or that the link has changed. Associated with these
Messages are a set of Data Items - information that describes the Messages are a set of Data Items - information that describes the
remote node (e.g., address information), and/or the characteristics remote node (e.g., address information), and/or the characteristics
of the link to the remote node. Throughout this document, we refer of the link to the remote node. Throughout this document, we refer
to a modems/routers participating in a DLEP session as 'DLEP to a modems/routers participating in a DLEP session as 'DLEP
skipping to change at page 8, line 19 skipping to change at page 7, line 36
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. A router and modem form sessions exist for each modem or connection. A router and modem form
a session by completing the discovery and initialization process. a session by completing the discovery and initialization process.
This router-modem session persists unless or until it either (1) This router-modem session persists unless or until it either (1)
times out, based on the absence of DLEP traffic (including times out, based on the absence of DLEP traffic (including
heartbeats), or (2) is explicitly torn down by one of the DLEP heartbeats), or (2) is explicitly torn down by one of the DLEP
participants. participants.
2.1. Destinations
The router/modem session provides a carrier for information exchange The router/modem session provides a carrier for information exchange
concerning 'destinations' that are available via the modem device. concerning 'destinations' that are available via the modem device.
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, addressable location that can be reached via represent a specific, addressable location that can be reached via
the link(s) managed by the modem. the link(s) managed by the modem.
The DLEP Messages 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 destinations information base representing the physical and logical destinations
accessible via the modem device, as well as the link characteristics accessible via the modem device, as well as the link characteristics
to those destinations. to those destinations.
DLEP identifies destinations by using the MAC address for delivering
data traffic. No manipulation or substitution is performed; the MAC
address supplied in all destination Messages is used as the
Destination MAC address. DLEP therefore requires that MAC addresses
are unique within the context of a router-modem session.
The reliance on MAC addresses by DLEP forces the requirement that
DLEP participants are on a single segment (either physical or
logically, via tunneling protocols) at Layer 2.
A destination can be either physical or logical. The example of a A destination can be either physical or logical. The example of a
physical destination would be that of a remote, far-end router physical destination would be that of a remote, far-end router
attached via the variable-quality network. It should be noted that attached via the variable-quality network. It should be noted that
for physical destinations the MAC address is the address of the far- for physical destinations the MAC address is the address of the far-
end router, not the modem. end router, not the modem.
The example of a logical destination is Multicast. Multicast traffic The example of a logical destination is Multicast. Multicast traffic
destined for the variable-quality network (the network accessed via destined for the variable-quality network (the network accessed via
the modem) is handled in IP networks by deriving a Layer 2 MAC the modem) is handled in IP networks by deriving a Layer 2 MAC
address based on the Layer 3 address. Leveraging on this scheme, address based on the Layer 3 address. Leveraging on this scheme,
skipping to change at page 9, line 16 skipping to change at page 8, line 24
To support these logical destinations, one of the DLEP participants To support these logical destinations, one of the DLEP participants
(typically, the router) informs the other as to the existence of the (typically, the router) informs the other as to the existence of the
logical destination. The modem, once it is aware of the existence of logical destination. The modem, once it is aware of the existence of
this logical destination, reports link characteristics just as it this logical destination, reports link characteristics just as it
would for any other destination in the network. The specific would for any other destination in the network. The specific
algorithms a modem would use to derive metrics on logical algorithms a modem would use to derive metrics on logical
destinations are outside the scope of this specification, and is left destinations are outside the scope of this specification, and is left
to specific implementations to decide. to specific implementations to decide.
In all cases, when this specification uses the term destination, it
refers to the addressable locations, either logical or physical, that
are accessible by the radio link(s).
3. Extensions
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. will in all likelihood be necessary as more link types are used.
Such extensions are defined as additional Messages, Data Items and/or Such extensions are defined as additional Messages, Data Items and/or
status codes, and associated rules of behavior, that are not defined status codes, and associated rules of behavior, that are not defined
in this document. DLEP contains a standard mechanism for router and in this document. DLEP contains a standard mechanism for router and
modem implementations to negotiate the available extensions to use on modem implementations to negotiate the available extensions to use on
a per-session basis. a per-session basis.
2.1. Assumptions 3.1. Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14, RFC 2119 [RFC2119].
DLEP MUST be implemented on a single Layer 2 domain. The protocol
identifies next-hop destinations by using the MAC address for
delivering data traffic. No manipulation or substitution is
performed; the MAC address supplied in all DLEP Messages is used as
the Destination MAC address for frames emitted by the participating
router. MAC addresses MUST be unique within the context of router-
modem session.
To enforce the single Layer 2 domain, implementations MUST support
The Generalized TTL Security Mechanism [RFC5082].
DLEP specifies UDP multicast for single-hop discovery signaling, and DLEP specifies UDP multicast for single-hop discovery signaling, and
TCP for transport of the Messages. Therefore, DLEP assumes that the TCP for transport of the Messages. Modems and routers participating
modem and router have topologically consistent IP addresses assigned. in DLEP sessions MUST 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. Implementations MUST adhere to the procedure documented
in [RFC5082] for all DLEP Messages (TCP traffic).
In order to keep the DLEP discovery Signals, which are multicast UDP-
based, limited to the same Layer 2 domain, implementations MUST set
the TTL of all DLEP Signals to 1, and MUST check for TTL = 1 on
receipt of DLEP Signals. Any signal received with a TTL not equal to
1 MUST be discarded.
DLEP relies on the guaranteed delivery of its Messages between router DLEP relies on the guaranteed delivery of its Messages between router
and modem, once the 1 hop discovery process is complete, hence, the and modem, once the 1 hop discovery process is complete, hence, the
specification of TCP to carry the Messages. Other reliable specification of TCP to carry the Messages. Other reliable
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 further assumes that security of the implementations (e.g., DLEP further requires that security of the implementations (e.g.,
authentication of stations, encryption of traffic, or both) is dealt authentication of stations, encryption of traffic, or both) is dealt
with by utilizing Layer 2 security techniques. This reliance on with by utilizing Layer 2 security techniques. This reliance on
Layer 2 mechanisms secures all DLEP Messages - both the UDP discovery Layer 2 mechanisms secures all DLEP Messages - both the UDP discovery
Signals and the TCP control Messages. Signals and the TCP control Messages.
3. 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 by a 'best effort', incorporating all metrics have been calculated by a 'best effort', incorporating all
pertinent data that is available to the modem device. pertinent data that is available to the modem device. Metrics based
on large enough sample sizes will preclude short traffic bursts from
adversely skewing reported values.
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 per-session (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. In cases where metrics are provided at session receive metrics. In cases where metrics are provided at session
level, the router propagates the metrics to all entries in its level, the router propagates the metrics to all entries in its
information base for destinations that are accessed via the modem. information base for destinations that are accessed via the modem.
DLEP modems announce all metric Data Items that will be reported DLEP modems announce all metric Data Items that will be reported
during the session, and provide default values for those metrics, in during the session, and provide default values for those metrics, in
the Session Initialization Response Message (Section 9.6). In order the Session Initialization Response Message (Section 10.6). In order
to use a metric type that was not included in the Session to use a metric type that was not included in the Session
Initialization Response Message, modem implementations terminate the Initialization Response Message, modem implementations terminate the
session with the router (via the Session Terminate Message session with the router (via the Session Terminate Message
(Section 9.9)), and establish a new session. (Section 10.9)), and establish a new session.
A DLEP modem can send metrics both in a session context, via the A DLEP modem can send metrics both in a session context, via the
Session Update Message (Section 9.7), and a specific destination Session Update Message (Section 10.7), and a specific destination
context, via the Destination Update Message (Section 9.17), at any context, via the Destination Update Message (Section 10.17), at any
time. The most recently received metric value takes precedence over time. The most recently received metric value takes precedence over
any earlier value, regardless of context - that is: any earlier value, regardless of context - that is:
1. If the router receives metrics in a specific destination context 1. If the router receives metrics in a specific destination context
(via the Destination Update Message), then the specific (via the Destination Update Message), then the specific
destination is updated with the new metric. destination is updated with the new metric.
2. If the router receives metrics in a session-wide context (via the 2. If the router receives metrics in a session-wide context (via the
Session Update Message), then the metrics for all destinations Session Update Message), then the metrics for all destinations
accessed via the modem are updated with the new metric. accessed via the modem are updated with the new metric.
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 can report metrics only once changing) link metric characteristics can report metrics only once
for a given destination (or once on a session-wide basis, if all for a given destination (or once on a session-wide basis, if all
connections via the modem are of this static nature). connections via the modem are of this static nature).
In addition to communicating existing metrics about the link, DLEP In addition to communicating existing metrics about the link, DLEP
provides a Message allowing a router to request a different datarate provides a Message allowing a router to request a different datarate
or latency from the modem. This Message is the Link Characteristics or latency from the modem. This Message is the Link Characteristics
Request Message (Section 9.18), and gives the router the ability to Request Message (Section 10.18), and gives the router the ability to
deal with requisite increases (or decreases) of allocated datarate/ deal with requisite increases (or decreases) of allocated datarate/
latency in demand-based schemes in a more deterministic manner. latency in demand-based schemes in a more deterministic manner.
4. DLEP Session Flow 5. DLEP Session Flow
All DLEP participants of a session transition through a number of All DLEP participants of a session transition through a number of
distinct states during the lifetime of a DLEP session: distinct states during the lifetime of a DLEP session:
o Peer Discovery o Peer Discovery
o Session Initialization o Session Initialization
o In-Session o In-Session
o Session Termination o Session Termination
o Session Reset o Session Reset
Modems, and routers supporting DLEP discovery, transition through all Modems, and routers supporting DLEP discovery, transition through all
five (5) of the above states. Routers that rely on preconfigured TCP five (5) of the above states. Routers that rely on preconfigured TCP
address/port information start in the Session Initialization state. address/port information start in the Session Initialization state.
Modems MUST support the Peer Discovery state. Modems MUST support the Peer Discovery state.
4.1. Peer Discovery State 5.1. Peer Discovery State
In the Peer Discovery state, routers that support DLEP discovery MUST In the Peer Discovery state, routers that support DLEP discovery MUST
send Peer Discovery Signals (Section 9.3) to initiate modem send Peer Discovery Signals (Section 10.3) to initiate modem
discovery. discovery.
The router implementation then waits for a Peer Offer Signal The router implementation then waits for a Peer Offer Signal
(Section 9.4) response from a potential DLEP modem. While in the (Section 10.4) response from a potential DLEP modem. While in the
Peer Discovery state, Peer Discovery Signals MUST be sent repeatedly Peer Discovery state, Peer Discovery Signals MUST be sent repeatedly
by a DLEP router, at regular intervals. The interval MUST be a by a DLEP router, at regular intervals. The interval MUST be a
minimum of one second; it SHOULD be a configurable parameter. Note minimum of one second; it SHOULD be a configurable parameter. Note
that this operation (sending Peer Discovery and waiting for Peer that this operation (sending Peer Discovery and waiting for Peer
Offer) is outside the DLEP Transaction Model (Section 5), as the Offer) is outside the DLEP Transaction Model (Section 6), as the
Transaction Model only describes Messages on a TCP session. Transaction Model only describes Messages on a TCP session.
Routers MUST use one or more of each of the modem address/port Routers MUST use one or more of each of the modem address/port
combinations from the Peer Offer Signal or, when no Connection Point combinations from the Peer Offer Signal or, when no Connection Point
Data Items are present, from a priori configuration to establish a Data Items are present, from a priori configuration to establish a
new TCP connection to the modem. If more than one modem address/port new TCP connection to the modem. If more than one modem address/port
combinations is provided, router implementations MAY use their own combinations is provided, router implementations MAY use their own
heuristics to determine the order in which they are tried. If a TCP heuristics to determine the order in which they are tried. If a TCP
connection cannot be achieved using any of the address/port connection cannot be achieved using any of the address/port
combinations and the Discovery mechanism is in use, then the router combinations and the Discovery mechanism is in use, then the router
SHOULD resume issuing Peer Discovery Signals. If no Connection Point SHOULD resume issuing Peer Discovery Signals. If no Connection Point
Data Items are included in the Peer Offer Signal, the router MUST use Data Items are included in the Peer Offer Signal, the router MUST use
the source address of the UDP packet containing the Signal as the IP the source address of the UDP packet containing the Peer Offer Signal
address, and the DLEP well-known port number. as the IP address, and the DLEP well-known port number.
In the Peer Discovery state, the modem implementation MUST listen for In the Peer Discovery state, the modem implementation MUST listen for
incoming Peer Discovery Signals on the DLEP well-known IPv6 and/or incoming Peer Discovery Signals on the DLEP well-known IPv6 and/or
IPv4 link-local multicast address and port. On receipt of a valid IPv4 link-local multicast address and port. On receipt of a valid
Peer Discovery Signal, it MUST reply with a Peer Offer Signal. Peer Discovery Signal, it MUST reply with a Peer Offer Signal.
Modems MUST be prepared to accept a TCP connection from a router that Modems MUST be prepared to accept a TCP connection from a router that
is not using the Discovery mechanism, i.e. a connection attempt that is not using the Discovery mechanism, i.e. a connection attempt that
occurs without a preceding Peer Discovery Signal. occurs without a preceding Peer Discovery Signal.
Upon establishment of a TCP connection, both modem and router enter Upon establishment of a TCP connection, both modem and router enter
the Session Initialization state. It is up to the router the Session Initialization state. It is up to the router
implementation if Peer Discovery Signals continue to be sent after implementation if Peer Discovery Signals continue to be sent after
the device has transitioned to the Session Initialization state. the device has transitioned to the Session Initialization state.
Modem implementations MUST silently ignore Peer Discovery Signals Modem implementations MUST silently ignore Peer Discovery Signals
from a router with which it already has a TCP connection. from a router with which it already has a TCP connection.
4.2. Session Initialization State 5.2. Session Initialization State
On entering the Session Initialization state, the router MUST send a On entering the Session Initialization state, the router MUST send a
Session Initialization Message (Section 9.5) to the modem. The Session Initialization Message (Section 10.5) to the modem. The
router MUST then wait for receipt of a Session Initialization router MUST then wait for receipt of a Session Initialization
Response Message (Section 9.6) from the modem. Receipt of the Response Message (Section 10.6) from the modem. Receipt of the
Session Initialization Response Message containing a Status Data Item Session Initialization Response Message containing a Status Data Item
(Section 10.1) with status code set to 0 'Success', see Table 4, (Section 11.1) with status code set to 0 'Success', see Table 2,
indicates that the modem has received and processed the Session indicates that the modem has received and processed the Session
Initialization Message, and the router MUST transition to the In- Initialization Message, and the router MUST transition to the In-
Session state. Session state.
On entering the Session Initialization state, the modem MUST wait for On entering the Session Initialization state, the modem MUST wait for
receipt of a Session Initialization Message from the router. Upon receipt of a Session Initialization Message from the router. Upon
receipt of a Session Initialization Message, the modem MUST send a receipt of a Session Initialization Message, the modem MUST send a
Session Initialization Response Message, and the session MUST Session Initialization Response Message, and the session MUST
transition to the In-Session state. If the modem receives any transition to the In-Session state. If the modem receives any
Message other than Session Initialization, or it fails to parse the Message other than Session Initialization, or it fails to parse the
received Message, it MUST NOT send any Message, and MUST terminate received Message, it MUST NOT send any Message, and MUST terminate
the TCP connection and transition to the Session Reset state. the TCP connection and transition to the Session Reset state.
DLEP provides an extension negotiation capability to be used in the DLEP provides an extension negotiation capability to be used in the
Session Initialization state, see Section 6. Extensions supported by Session Initialization state, see Section 3. Extensions supported by
an implementation MUST be declared to potential DLEP participants an implementation MUST be declared to potential DLEP participants
using the Extensions Supported Data Item (Section 10.6). Once both using the Extensions Supported Data Item (Section 11.6). Once both
DLEP participants have exchanged initialization Messages, an DLEP participants have exchanged initialization Messages, an
implementation MUST NOT emit any Message, Signal, Data Item or status implementation MUST NOT emit any Message, Signal, Data Item or status
code associated with an extension that was not specified in the code associated with an extension that was not specified in the
received initialization Message from its peer. received initialization Message from its peer.
4.3. In-Session State 5.3. In-Session State
In the In-Session state, Messages can flow in both directions between In the In-Session state, Messages can flow in both directions between
DLEP participants, indicating changes to the session state, the DLEP participants, indicating changes to the session state, the
arrival or departure of reachable destinations, or changes of the arrival or departure of reachable destinations, or changes of the
state of the links to the destinations. state of the links to the destinations.
The In-Session state is maintained until one of the following The In-Session state is maintained until one of the following
conditions occur: conditions occur:
o The implementation terminates the session by sending a Session o The implementation terminates the session by sending a Session
Termination Message (Section 9.9), or, Termination Message (Section 10.9), or,
o Its peer terminates the session, indicated by receiving a Session o Its peer terminates the session, indicated by receiving a Session
Termination Message. Termination Message.
The implementation MUST then transition to the Session Termination The implementation MUST then transition to the Session Termination
state. state.
4.3.1. Heartbeats 5.3.1. Heartbeats
In order to maintain the In-Session state, periodic Heartbeat In order to maintain the In-Session state, periodic Heartbeat
Messages (Section 9.20) MUST be exchanged between router and modem. Messages (Section 10.20) MUST be exchanged between router and modem.
These Messages are intended to keep the session alive, and to verify These Messages are intended to keep the session alive, and to verify
bidirectional connectivity between the two DLEP participants. bidirectional connectivity between the two DLEP participants.
Each DLEP participant is responsible for the creation of Heartbeat Each DLEP participant is responsible for the creation of Heartbeat
Messages. Messages.
Receipt of any valid DLEP Message MUST reset the heartbeat interval Receipt of any valid DLEP Message MUST reset the heartbeat interval
timer (i.e., valid DLEP Messages take the place of, and obviate the timer (i.e., valid DLEP Messages take the place of, and obviate the
need for, additional Heartbeat Messages). need for, additional Heartbeat Messages).
Implementations MUST allow a minimum of two (2) heartbeat intervals Implementations MUST allow a minimum of two (2) heartbeat intervals
to expire with no Messages from its peer before terminating the to expire with no Messages from its peer before terminating the
session. When terminating the session, a Session Termination Message session. When terminating the session, a Session Termination Message
containing a Status Data Item (Section 10.1) with status code set to containing a Status Data Item (Section 11.1) with status code set to
132 'Timed Out', see Table 4, MUST be sent, and then the 132 'Timed Out', see Table 2, MUST be sent, and then the
implementation MUST transition to the Session Termination state. implementation MUST transition to the Session Termination state.
4.4. Session Termination State 5.4. Session Termination State
When an implementation enters the Session Termination state after When an implementation enters the Session Termination state after
sending a Session Termination Message (Section 9.9) as the result of sending a Session Termination Message (Section 10.9) as the result of
an invalid Message or error, it MUST wait for a Session Termination an invalid Message or error, it MUST wait for a Session Termination
Response Message (Section 9.10) from its peer. Senders SHOULD allow Response Message (Section 10.10) from its peer. Senders SHOULD allow
four (4) heartbeat intervals to expire before assuming that its peer four (4) heartbeat intervals to expire before assuming that its peer
is unresponsive, and continuing with session termination. Any other is unresponsive, and continuing with session termination. Any other
Message received while waiting MUST be silently ignored. Message received while waiting MUST be silently ignored.
When the sender of the Session Termination Message receives a Session When the sender of the Session Termination Message receives a Session
Termination Response Message from its peer, or times out, it MUST Termination Response Message from its peer, or times out, it MUST
transition to the Session Reset state. transition to the Session Reset state.
When an implementation receives a Session Termination Message from When an implementation receives a Session Termination Message from
its peer, it enters the Session Termination state and then it MUST its peer, it enters the Session Termination state and then it MUST
immediately send a Session Termination Response and transition to the immediately send a Session Termination Response and transition to the
Session Reset state. Session Reset state.
4.5. Session Reset state 5.5. Session Reset state
In the Session Reset state the implementation MUST perform the In the Session Reset state the implementation MUST perform the
following actions: following actions:
o Release all resources allocated for the session. o Release all resources allocated for the session.
o Eliminate all destinations in the information base represented by o Eliminate all destinations in the information base represented by
the session. Destination Down Messages (Section 9.15) MUST NOT be the session. Destination Down Messages (Section 10.15) MUST NOT
sent. be sent.
o Terminate the TCP connection. o Terminate the TCP connection.
Having completed these actions the implementation SHOULD return to Having completed these actions the implementation SHOULD return to
the relevant initial state: Peer Discovery for modems; either Peer the relevant initial state: Peer Discovery for modems; either Peer
Discovery or Session Initialization for routers, depending on Discovery or Session Initialization for routers, depending on
configuration. configuration.
4.5.1. Unexpected TCP connection termination 5.5.1. Unexpected TCP connection termination
If the TCP connection between DLEP participants is terminated when an If the TCP connection between DLEP participants is terminated when an
implementation is not in the Session Reset state, the implementation implementation is not in the Session Reset state, the implementation
MUST immediately transition to the Session Reset state. MUST immediately transition to the Session Reset state.
5. Transaction Model 6. Transaction Model
DLEP defines a simple Message transaction model: Only one request per DLEP defines a simple Message transaction model: Only one request per
destination may be in progress at a time per session. A Message destination may be in progress at a time per session. A Message
transaction is considered complete when a response matching a transaction is considered complete when a response matching a
previously issued request is received. If a DLEP participant previously issued request is received. If a DLEP participant
receives a request for a destination for which there is already an receives a request for a destination for which there is already an
outstanding request, the implementation MUST terminate the session by outstanding request, the implementation MUST terminate the session by
issuing a Session Termination Message (Section 9.9) containing a issuing a Session Termination Message (Section 10.9) containing a
Status Data Item (Section 10.1) with status code set to 129 Status Data Item (Section 11.1) with status code set to 129
'Unexpected Message', see Table 4, and transition to the Session 'Unexpected Message', see Table 2, and transition to the Session
Termination state. There is no restriction to the total number of Termination state. There is no restriction to the total number of
Message transactions in progress at a time, as long as each Message transactions in progress at a time, as long as each
transaction refers to a different destination. transaction refers to a different destination.
It should be noted that some requests may take a considerable amount It should be noted that some requests may take a considerable amount
of time for some DLEP participants to complete, for example a modem of time for some DLEP participants to complete, for example a modem
handling a multicast destination up request may have to perform a handling a multicast destination up request may have to perform a
complex network reconfiguration. A sending implementation MUST be complex network reconfiguration. A sending implementation MUST be
able to handle such long running transactions gracefully. able to handle such long running transactions gracefully.
Additionally, only one session request, e.g. a Session Initialization Additionally, only one session request, e.g. a Session Initialization
Message (Section 9.5), may be in progress at a time per session. As Message (Section 10.5), may be in progress at a time per session. As
above, a session transaction is considered complete when a response above, a session transaction is considered complete when a response
matching a previously issued request is received. If a DLEP matching a previously issued request is received. If a DLEP
participant receives a session request while there is already a participant receives a session request while there is already a
session request in progress, it MUST terminate the session by issuing session request in progress, it MUST terminate the session by issuing
a Session Termination Message containing a Status Data Item with a Session Termination Message containing a Status Data Item with
status code set to 129 'Unexpected Message', and transition to the status code set to 129 'Unexpected Message', and transition to the
Session Termination state. Only the Session Termination Message may Session Termination state. Only the Session Termination Message may
be issued when a session transaction is in progress. Heartbeat be issued when a session transaction is in progress. Heartbeat
Messages (Section 9.20) MUST NOT be considered part of a session Messages (Section 10.20) MUST NOT be considered part of a session
transaction. transaction.
DLEP transactions do not time out and are not cancellable. An DLEP transactions do not time out and are not cancellable. An
implementation can detect if its peer has failed in some way by use implementation can detect if its peer has failed in some way by use
of the session heartbeat mechanism during the In-Session state, see of the session heartbeat mechanism during the In-Session state, see
Section 4.3. Section 5.3.
6. Extensions 7. Extensions
Extensions MUST be negotiated on a per-session basis during session Extensions MUST be negotiated on a per-session basis during session
initialization via the Extensions Supported mechanism. initialization via the Extensions Supported mechanism.
Implementations are not required to support any extension in order to Implementations are not required to support any extension in order to
be considered DLEP compliant. An extension document, describing the be considered DLEP compliant. An extension document, describing the
operation of a credit windowing scheme for flow control, is described operation of a credit windowing scheme for flow control, is described
in [CREDIT]. in [CREDIT].
If interoperable protocol extensions are required, they will need to If interoperable protocol extensions are required, they will need to
be standardized either as an update to this document, or as an be standardized either as an update to this document, or as an
additional stand-alone specification. The requests for IANA- additional stand-alone specification. The requests for IANA-
controlled registries in this document contain sufficient Reserved controlled registries in this document contain sufficient Reserved
space for DLEP Signals, Messages, Data Items and status codes to space for DLEP Signals, Messages, Data Items and status codes to
accommodate future extensions to the protocol. accommodate future extensions to the protocol.
As multiple protocol extensions MAY be announced during session As multiple protocol extensions MAY be announced during session
initialization, authors of protocol extensions need to consider the initialization, authors of protocol extensions need to consider the
interaction of their extension with other published extensions, and interaction of their extension with other published extensions, and
specify any incompatibilities. specify any incompatibilities.
6.1. Experiments 7.1. Experiments
This document requests Private Use numbering space in the DLEP This document requests Private Use numbering space in the DLEP
Signal, Message, Data Item and status code registries for Signal, Message, Data Item and status code registries for
experimental extensions. The intent is to allow for experimentation experimental extensions. The intent is to allow for experimentation
with new Signals, Messages, Data Items, and/or status codes, while with new Signals, Messages, Data Items, and/or status codes, while
still retaining the documented DLEP behavior. still retaining the documented DLEP behavior.
Use of the Private Use Signals, Messages, Data Items, status codes, Use of the Private Use Signals, Messages, Data Items, status codes,
or behaviors MUST be announced as DLEP Extensions, during session or behaviors MUST be announced as DLEP Extensions, during session
initialization, using extension identifiers from the Private Use initialization, using extension identifiers from the Private Use
space in the Extensions Supported registry (Table 5), with a value space in the Extensions Supported registry (Table 3), with a value
agreed upon (a priori) between the participants. DLEP extensions agreed upon (a priori) between the participants. DLEP extensions
using the Private Use numbering space are commonly referred to as using the Private Use numbering space are commonly referred to as
Experiments. Experiments.
Multiple experiments MAY be announced in the Session Initialization Multiple experiments MAY be announced in the Session Initialization
Messages. However, use of multiple experiments in a single session Messages. However, use of multiple experiments in a single session
could lead to interoperability issues or unexpected results (e.g., could lead to interoperability issues or unexpected results (e.g.,
clashes of experimental Signals, Messages, Data Items and/or status clashes of experimental Signals, Messages, Data Items and/or status
code types), and is therefore discouraged. It is left to code types), and is therefore discouraged. It is left to
implementations to determine the correct processing path (e.g., a implementations to determine the correct processing path (e.g., a
decision on whether to terminate the session, or to establish a decision on whether to terminate the session, or to establish a
precedence of the conflicting definitions) if such conflicts arise. precedence of the conflicting definitions) if such conflicts arise.
7. Scalability 8. Scalability
The protocol is intended to support thousands of destinations on a The protocol is intended to support thousands of destinations on a
given modem/router pair. At large scale, implementations SHOULD given modem/router pair. At large scale, implementations SHOULD
consider employing techniques to prevent flooding its peer with a consider employing techniques to prevent flooding its peer with a
large number of Messages in a short time. It is RECOMMENDED that large number of Messages in a short time. For example, a dampening
implementations consider a dampening algorithm to prevent a flapping algorithm could be employed to prevent a flapping device from
device from generating a large number of Destination Up/Destination generating a large number of Destination Up/Destination Down
Down Messages, for example. Messages.
Implementations SHOULD also consider techniques such as a hysteresis Also, use of techniques such as a hysteresis can lessen the impact of
to lessen the impact of rapid, minor fluctuations in link quality. rapid, minor fluctuations in link quality. The specific algorithms
The specific algorithms to be used for handling flapping destinations for handling flapping destinations and minor changes in link quality
and minor changes in link quality are outside the scope of this are outside the scope of this specification.
specification.
8. DLEP Signal and Message Structure 9. DLEP Signal and Message Structure
DLEP defines two protocol units used in two different ways: Signals DLEP defines two protocol units used in two different ways: Signals
and Messages. Signals are only used in the Discovery mechanism and and Messages. Signals are only used in the Discovery mechanism and
are carried in UDP datagrams. Messages are used bi-directionally are carried in UDP datagrams. Messages are used bi-directionally
over a TCP connection between the participants, in the Session over a TCP connection between the participants, in the Session
Initialization, In-Session and Session Termination states. Initialization, In-Session and Session Termination states.
Both Signals and Messages consist of a Header followed by an Both Signals and Messages consist of a Header followed by an
unordered list of Data Items. Headers consist of Type and Length unordered list of Data Items. Headers consist of Type and Length
information, while Data Items are encoded as TLV (Type-Length-Value) information, while Data Items are encoded as TLV (Type-Length-Value)
skipping to change at page 17, line 15 skipping to change at page 17, line 17
Message. 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
Header, and the acceptability of duplicate Data Items is defined by Header, and the acceptability of duplicate Data Items is defined by
the definition of the Signal or Message declared by the type in the the definition of the Signal or Message declared by the type in the
Header. Header.
All integers in Header fields and values MUST be in network byte- All integers in Header fields and values MUST be in network byte-
order. order.
8.1. DLEP Signal Header 9.1. DLEP Signal Header
The DLEP Signal Header contains the following fields: The DLEP Signal Header 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 'D' | 'L' | 'E' | 'P' | | 'D' | 'L' | 'E' | 'P' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signal Type | Length | | Signal Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 17, line 43 skipping to change at page 17, line 45
Signal Type values defined in this document. Signal Type values defined in this document.
Length: The length in octets, expressed as a 16-bit unsigned Length: The length in octets, expressed as a 16-bit unsigned
integer, of all of the DLEP Data Items contained in this Signal. integer, of all of the DLEP Data Items contained in this Signal.
This length MUST NOT include the length of the Signal Header This length MUST NOT include the length of the Signal Header
itself. itself.
The DLEP Signal Header is immediately followed by zero or more DLEP The DLEP Signal Header is immediately followed by zero or more DLEP
Data Items, encoded in TLVs, as defined in this document. Data Items, encoded in TLVs, as defined in this document.
8.2. DLEP Message Header 9.2. DLEP Message Header
The DLEP Message Header contains the following fields: The DLEP Message Header 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Type | Length | | Message Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: DLEP Message Header Figure 4: DLEP Message Header
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Message Type values defined in this document. Message Type values defined in this document.
Length: The length in octets, expressed as a 16-bit unsigned Length: The length in octets, expressed as a 16-bit unsigned
integer, of all of the DLEP Data Items contained in this Message. integer, of all of the DLEP Data Items contained in this Message.
This length MUST NOT include the length of the Message Header This length MUST NOT include the length of the Message Header
itself. itself.
The DLEP Message Header is immediately followed by zero or more DLEP The DLEP Message Header is immediately followed by zero or more DLEP
Data Items, encoded in TLVs, as defined in this document. Data Items, encoded in TLVs, as defined in this document.
8.3. DLEP Generic Data Item 9.3. 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 | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value... : | Value... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Data Item Type: A 16-bit unsigned integer field specifying the type Data Item Type: A 16-bit unsigned integer field specifying the type
of Data Item being sent. of Data Item being sent.
Length: The length in octets, expressed as a 16-bit unsigned Length: The length in octets, expressed as a 16-bit unsigned
integer, of the Value field of the Data Item. This length MUST integer, of the Value field of the Data Item. This length MUST
NOT include the length of the Data Item Type and Length fields. NOT include the length of the Data Item Type and Length fields.
Value: A field of <Length> octets, which contains data specific to a Value: A field of <Length> octets, which contains data specific to a
particular Data Item. particular Data Item.
9. DLEP Signals and Messages 10. DLEP Signals and Messages
10.1. General Processing Rules
Following is the set of core Signals and Messages that MUST be
recognized by a DLEP compliant implementation. As mentioned before,
not all Messages may be used during a session, but an implementation
MUST correctly process these Signals and Messages when received.
The core DLEP Signals are:
+--------------+-----------------------------------------+
| Type Code | Description |
+--------------+-----------------------------------------+
| 0 | Reserved |
| 1 | Peer Discovery Signal (Section 9.3) |
| 2 | Peer Offer Signal (Section 9.4) |
| 3-65519 | Reserved for future extensions |
| 65520-65534 | Private Use. Available for experiments |
| 65535 | Reserved |
+--------------+-----------------------------------------+
Table 1: DLEP Signal types
The core DLEP Messages are:
+--------------+----------------------------------------------------+
| Type Code | Description |
+--------------+----------------------------------------------------+
| 0 | Reserved |
| 1 | Session Initialization Message (Section 9.5) |
| 2 | Session Initialization Response Message (Section |
| | 9.6) |
| 3 | Session Update Message (Section 9.7) |
| 4 | Session Update Response Message (Section 9.8) |
| 5 | Session Termination Message (Section 9.9) |
| 6 | Session Termination Response Message (Section |
| | 9.10) |
| 7 | Destination Up Message (Section 9.11) |
| 8 | Destination Up Response Message (Section 9.12) |
| 9 | Destination Announce Message (Section 9.13) |
| 10 | Destination Announce Response Message (Section |
| | 9.14) |
| 11 | Destination Down Message (Section 9.15) |
| 12 | Destination Down Response Message (Section 9.16) |
| 13 | Destination Update Message (Section 9.17) |
| 14 | Link Characteristics Request Message (Section |
| | 9.18) |
| 15 | Link Characteristics Response Message (Section |
| | 9.19) |
| 16 | Heartbeat Message (Section 9.20) |
| 17-65519 | Reserved for future extensions |
| 65520-65534 | Private Use. Available for experiments |
| 65535 | Reserved |
+--------------+----------------------------------------------------+
Table 2: DLEP Message types
9.1. General Processing Rules
If an unrecognized, or unexpected Signal is received, or a received If an unrecognized, or unexpected Signal is received, or a received
Signal contains unrecognized, invalid, or disallowed duplicate Data Signal contains unrecognized, invalid, or disallowed duplicate Data
Items, the receiving implementation MUST ignore the Signal. Items, the receiving implementation MUST ignore the Signal.
If a Signal is received with a TTL value that is NOT equal to 1, the
receiving implementation MUST ignore the Signal.
If a received Message contains a TTL value other than 255, the
receiving implementation MUST close the session, and transition to
the Session Termination state.
If an unrecognized Message is received, the receiving implementation If an unrecognized Message is received, the receiving implementation
MUST issue a Session Termination Message (Section 9.9) containing a MUST issue a Session Termination Message (Section 10.9) containing a
Status Data Item (Section 10.1) with status code set to 128 'Unknown Status Data Item (Section 11.1) with status code set to 128 'Unknown
Message', see Table 4, and transition to the Session Termination Message', see Table 2, and transition to the Session Termination
state. state.
If an unexpected Message is received, the receiving implementation If an unexpected Message is received, the receiving implementation
MUST issue a Session Termination Message containing a Status Data MUST issue a Session Termination Message containing a Status Data
Item with status code set to 129 'Unexpected Message', and transition Item with status code set to 129 'Unexpected Message', and transition
to the Session Termination state. to the Session Termination state.
If a received Message contains unrecognized, invalid, or disallowed If a received Message contains unrecognized, invalid, or disallowed
duplicate Data Items, the receiving implementation MUST issue a duplicate Data Items, the receiving implementation MUST issue a
Session Termination Message containing a Status Data Item with status Session Termination Message containing a Status Data Item with status
code set to 130 'Invalid Data', and transition to the Session code set to 130 'Invalid Data', and transition to the Session
Termination state. Termination state.
Prior to the exchange of Destination Up (Section 9.11) and Prior to the exchange of Destination Up (Section 10.11) and
Destination Up Response (Section 9.12) Messages, or Destination Destination Up Response (Section 10.12) Messages, or Destination
Announce (Section 9.13) and Destination Announce Response Announce (Section 10.13) and Destination Announce Response
(Section 9.14) Messages, no Messages concerning a destination may be (Section 10.14) Messages, no Messages concerning a destination may be
sent. An implementation receiving any Message with such an sent. An implementation receiving any Message with such an
unannounced destination MUST terminate the session by issuing a unannounced destination MUST terminate the session by issuing a
Session Termination Message containing a Status Data Item with status Session Termination Message containing a Status Data Item with status
code set to 131 'Invalid Destination', and transition to the Session code set to 131 'Invalid Destination', and transition to the Session
Termination state. Termination state.
After exchanging Destination Down (Section 9.15) and Destination Down After exchanging Destination Down (Section 10.15) and Destination
Response (Section 9.16) Messages, no Messages concerning a Down Response (Section 10.16) Messages, no Messages concerning a
destination may be a sent until a new Destination Up or Destination destination may be a sent until a new Destination Up or Destination
Announce Message is sent. An implementation receiving a Message Announce Message is sent. An implementation receiving a Message
about a destination previously announced as 'down' MUST terminate the about a destination previously announced as 'down' MUST terminate the
session by issuing a Session Termination Message with a Status Data session by issuing a Session Termination Message with a Status Data
Item with status code set to 131 'Invalid Destination', and Item with status code set to 131 'Invalid Destination', and
transition to the Session Termination state. transition to the Session Termination state.
9.2. Status code processing 10.2. Status code processing
The behaviour of a DLEP participant receiving a Message containing a The behaviour of a DLEP participant receiving a Message containing a
Status Data Item (Section 10.1) is defined by the failure mode Status Data Item (Section 11.1) is defined by the failure mode
associated with the value of the status code field, see Table 4. All associated with the value of the status code field, see Table 2. All
status code values less than 100 have a failure mode of 'Continue', status code values less than 100 have a failure mode of 'Continue',
all other status codes have a failure mode of 'Terminate'. all other status codes have a failure mode of 'Terminate'.
A DLEP participant receiving any Message apart from Session A DLEP participant receiving any Message apart from Session
Termination Message (Section 9.9) containing a Status Data Item with Termination Message (Section 10.9) containing a Status Data Item with
a status code value with failure mode 'Terminate' MUST immediately a status code value with failure mode 'Terminate' MUST immediately
issue a Session Termination Message containing an identical Status issue a Session Termination Message containing an identical Status
Data Item, and then transition to the Session Termination state. Data Item, and then transition to the Session Termination state.
A DLEP participant receiving a Message containing a Status Data Item A DLEP participant receiving a Message containing a Status Data Item
with a status code value with failure mode 'Continue' can continue with a status code value with failure mode 'Continue' can continue
normal operation of the session. normal operation of the session.
9.3. Peer Discovery Signal 10.3. Peer Discovery Signal
A Peer Discovery Signal SHOULD be sent by a DLEP router to discover A Peer Discovery Signal SHOULD be sent by a DLEP router to discover
DLEP modems in the network, see Section 4.1. DLEP modems in the network, see Section 5.1.
A Peer Discovery Signal MUST be encoded within a UDP packet. The A Peer Discovery Signal MUST be encoded within a UDP packet. The
destination MUST be set to the DLEP well-known address and port destination MUST be set to the DLEP well-known address and port
number. For routers supporting both IPv4 and IPv6 DLEP operation, it number. For routers supporting both IPv4 and IPv6 DLEP operation, it
is RECOMMENDED that IPv6 be selected as the transport. The source IP is RECOMMENDED that IPv6 be selected as the transport. The source IP
address MUST be set to the router IP address associated with the DLEP address MUST be set to the router IP address associated with the DLEP
interface. There is no DLEP-specific restriction on source port. interface. There is no DLEP-specific restriction on source port.
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 1, from Table 1. Signal Header is set to 1 (see Signal Type Registration
(Section 13.2)).
The Peer Discovery Signal MAY contain a Peer Type Data Item The Peer Discovery Signal MAY contain a Peer Type Data Item
(Section 10.4). (Section 11.4).
9.4. Peer Offer Signal 10.4. 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
properly formatted and addressed Peer Discovery Signal (Section 9.3). properly formatted and addressed Peer Discovery Signal
(Section 10.3).
A Peer Offer Signal MUST be encoded within a UDP packet. The IP A Peer Offer Signal MUST be encoded within a UDP packet. The IP
destination MUST be set to the IP address and port number received in destination MUST be set to the IP address and port number received in
the corresponding Peer Discovery Signal. The source IP address MUST the corresponding Peer Discovery Signal. The source IP address MUST
be set to the modem's IP address associated with the DLEP interface. be set to the modem's IP address associated with the DLEP interface.
The source port number MUST be set to the DLEP well-known port The source port number MUST be set to the DLEP well-known port
number. The Peer Offer Signal completes the discovery process, see number. The Peer Offer Signal completes the discovery process, see
Section 4.1. Section 5.1.
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 2, from Table 1. Header is set to 2 (see Signal Type Registration (Section 13.2)).
The Peer Offer Signal MAY contain a Peer Type Data Item The Peer Offer Signal MAY contain a Peer Type Data Item
(Section 10.4). (Section 11.4).
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 10.2) o IPv4 Connection Point (Section 11.2)
o IPv6 Connection Point (Section 10.3) o IPv6 Connection Point (Section 11.3)
The IP Connection Point Data Items indicate the unicast address the The IP Connection Point Data Items indicate the unicast address the
router MUST use when connecting the DLEP TCP session. router MUST use when connecting the DLEP TCP session.
9.5. Session Initialization Message 10.5. Session Initialization Message
A Session Initialization Message MUST be sent by a DLEP router as the A Session Initialization Message MUST be sent by a DLEP router as the
first Message of the DLEP TCP session. It is sent by the router first Message of the DLEP TCP session. It is sent by the router
after a TCP connect to an address/port combination that was obtained after a TCP connect to an address/port combination that was obtained
either via receipt of a Peer Offer, or from a priori configuration. either via receipt of a Peer Offer, or from a priori configuration.
To construct a Session Initialization Message, the Message Type value To construct a Session Initialization Message, the Message Type value
in the Message Header is set to 1, from Table 2. in the Message Header is set to 1 (see Message Type Registration
(Section 13.3)).
The Session Initialization Message MUST contain a Heartbeat Interval The Session Initialization Message MUST contain a Heartbeat Interval
Data Item (Section 10.5). Data Item (Section 11.5).
The Session Initialization Message 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 10.4) o Peer Type (Section 11.4)
o Extensions Supported (Section 10.6) o Extensions Supported (Section 11.6)
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 Session Extensions Supported Data Item does not exist in a Session
Initialization Message, the modem MUST conclude that there is no Initialization Message, the modem MUST conclude that there is no
support for extensions in the router. support for extensions in the router.
DLEP Heartbeats are not fully established until receipt of the DLEP Heartbeats are not fully established until receipt of the
Session Initialization Response Message (Section 9.6), and therefore Session Initialization Response Message (Section 10.6), and therefore
implementations MUST use their own timeout and retry heuristics for implementations MUST use their own timeout and retry heuristics for
this Message. this Message.
As an exception to the general rule governing an implementation As an exception to the general rule governing an implementation
receiving an unrecognized Data Item in a Message, see Section 9.1, if receiving an unrecognized Data Item in a Message, see Section 10.1,
a Session Initialization Message contains one or more Extension if a Session Initialization Message contains one or more Extension
Supported Data Items announcing support for extensions that the Supported Data Items announcing support for extensions that the
implementation does not recognize, then the implementation MAY ignore implementation does not recognize, then the implementation MAY ignore
Data Items it does not recognize. Data Items it does not recognize.
9.6. Session Initialization Response Message 10.6. Session Initialization Response Message
A Session Initialization Response Message MUST be sent in response to A Session Initialization Response Message MUST be sent in response to
a received Session Initialization Message (Section 9.5). a received Session Initialization Message (Section 10.5).
To construct a Session Initialization Response Message, the Message To construct a Session Initialization Response Message, the Message
Type value in the Message Header is set to 2, from Table 2. Type value in the Message Header is set to 2 (see Message Type
Registration (Section 13.3)).
The Session Initialization Response Message MUST contain one of each The Session Initialization Response Message MUST contain one of each
of the following Data Items: of the following Data Items:
o Status (Section 10.1) o Status (Section 11.1)
o Heartbeat Interval (Section 10.5) o Heartbeat Interval (Section 11.5)
o Maximum Data Rate (Receive) (Section 10.12) o Maximum Data Rate (Receive) (Section 11.12)
o Maximum Data Rate (Transmit) (Section 10.13)
o Current Data Rate (Receive) (Section 10.14) o Maximum Data Rate (Transmit) (Section 11.13)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Receive) (Section 11.14)
o Latency (Section 10.16) o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 11.16)
The Session Initialization Response Message MUST contain one of each The Session Initialization Response Message MUST contain one of each
of the following Data Items, if the Data Item will be used during the of the following Data Items, if the Data Item will be used during the
lifetime of the session: lifetime of the session:
o Resources (Section 10.17) o Resources (Section 11.17)
o Relative Link Quality (Receive) (Section 10.18)
o Relative Link Quality (Transmit) (Section 10.19) o Relative Link Quality (Receive) (Section 11.18)
o Maximum Transmission Unit (MTU) (Section 10.20) o Relative Link Quality (Transmit) (Section 11.19)
o Maximum Transmission Unit (MTU) (Section 11.20)
The Session Initialization Response Message MAY contain one of each The Session Initialization Response Message MAY contain one of each
of the following Data Items: of the following Data Items:
o Peer Type (Section 10.4) o Peer Type (Section 11.4)
o Extensions Supported (Section 10.6) o Extensions Supported (Section 11.6)
The Session Initialization Response Message completes the DLEP The Session Initialization Response Message completes the DLEP
session establishment; the modem should transition to the In-Session session establishment; the modem should transition to the In-Session
state when the Message is sent, and the router should transition to state when the Message is sent, and the router should transition to
the In-Session state upon receipt of an acceptable Session the In-Session state upon receipt of an acceptable Session
Initialization Response Message. Initialization Response Message.
All supported metric Data Items MUST be included in the Session All supported metric Data Items MUST be included in the Session
Initialization Response Message, with default values to be used on a Initialization Response Message, with default values to be used on a
session-wide basis. This can be viewed as the modem 'declaring' all session-wide basis. This can be viewed as the modem 'declaring' all
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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 Session Initialization Supported Data Item does not exist in a Session Initialization
Response Message, the router MUST conclude that there is no support Response Message, the router MUST conclude that there is no support
for extensions in the modem. for extensions in the modem.
After the Session Initialization/Session Initialization Response After the Session Initialization/Session Initialization Response
Messages have been successfully exchanged, implementations MUST only Messages have been successfully exchanged, implementations MUST only
use extensions that are supported by both DLEP participants, see use extensions that are supported by both DLEP participants, see
Section 4.2. Section 5.2.
9.7. Session Update Message 10.7. Session Update Message
A Session Update Message MAY be sent by a DLEP participant to A Session Update Message MAY be sent by a DLEP participant to
indicate local Layer 3 address changes, or metric changes on a indicate local Layer 3 address changes, or metric changes on a
session-wide basis. session-wide basis.
To construct a Session Update Message, the Message Type value in the To construct a Session Update Message, the Message Type value in the
Message Header is set to 3, from Table 2. Message Header is set to 3 (see Message Type Registration
(Section 13.3)).
The Session Update Message MAY contain one of each of the following The Session Update Message MAY contain one of each of the following
Data Items: Data Items:
o Maximum Data Rate (Receive) (Section 10.12) o Maximum Data Rate (Receive) (Section 11.12)
o Maximum Data Rate (Transmit) (Section 11.13)
o Maximum Data Rate (Transmit) (Section 10.13)
o Current Data Rate (Receive) (Section 10.14) o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 10.16) o Latency (Section 11.16)
The Session Update Message MAY contain one of each of the following The Session Update Message MAY contain one of each of the following
Data Items, if the Data Item is in use by the session: Data Items, if the Data Item is in use by the session:
o Resources (Section 10.17) o Resources (Section 11.17)
o Relative Link Quality (Receive) (Section 10.18) o Relative Link Quality (Receive) (Section 11.18)
o Relative Link Quality (Transmit) (Section 10.19) o Relative Link Quality (Transmit) (Section 11.19)
o Maximum Transmission Unit (MTU) (Section 10.20) o Maximum Transmission Unit (MTU) (Section 11.20)
The Session Update Message MAY contain one or more of each of the The Session Update Message MAY contain one or more of each of the
following Data Items, with different values: following Data Items, with different values:
o IPv4 Address (Section 10.8) o IPv4 Address (Section 11.8)
o IPv6 Address (Section 10.9) o IPv6 Address (Section 11.9)
If metrics are supplied with the Session Update Message (e.g., If metrics are supplied with the Session Update Message (e.g.,
Maximum Data Rate), these metrics are considered to be session-wide, Maximum Data Rate), these metrics are considered to be session-wide,
and therefore MUST be applied to all destinations in the information and therefore MUST be applied to all destinations in the information
base associated with the DLEP session. This includes destinations base associated with the DLEP session. This includes destinations
for which metrics may have been stored based on received Destination for which metrics may have been stored based on received Destination
Update messages. Update messages.
It should be noted that Session Update Messages can be sent by both It should be noted that Session Update Messages can be sent by both
routers and modems. For example, addition of an IPv4 address to the routers and modems. For example, addition of an IPv4 address to the
router MAY prompt a Session Update Message to its attached modems. router MAY prompt a Session Update Message to its attached modems.
Also, for example, a modem that changes its Maximum Data Rate Also, for example, a modem that changes its Maximum Data Rate
(Receive) for all destinations MAY reflect that change via a Session (Receive) for all destinations MAY reflect that change via a Session
Update Message to its attached router(s). Update Message to 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
Message (Section 9.17) to their local routers with the new (or Message (Section 10.17) 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 ignore Address Data Items. SHOULD silently ignore Address Data Items.
9.8. Session Update Response Message 10.8. Session Update Response Message
A Session Update Response Message MUST be sent by a DLEP participant A Session Update Response Message MUST be sent by a DLEP participant
when a Session Update Message (Section 9.7) is received. when a Session Update Message (Section 10.7) is received.
To construct a Session Update Response Message, the Message Type To construct a Session Update Response Message, the Message Type
value in the Message Header is set to 4, from Table 2. value in the Message Header is set to 4 (see Message Type
Registration (Section 13.3)).
The Session Update Response Message MUST contain a Status Data Item The Session Update Response Message MUST contain a Status Data Item
(Section 10.1). (Section 11.1).
9.9. Session Termination Message 10.9. Session Termination Message
A Session Termination Message MUST be sent by a DLEP participant when A Session Termination Message MUST be sent by a DLEP participant when
the DLEP session needs to be terminated. the DLEP session needs to be terminated.
To construct a Session Termination Message, the Message Type value in To construct a Session Termination Message, the Message Type value in
the Message Header is set to 5, from Table 2. the Message Header is set to 5 (see Message Type Registration
(Section 13.3)).
The Session Termination Message MUST contain Status Data Item The Session Termination Message MUST contain Status Data Item
(Section 10.1). (Section 11.1).
It should be noted that Session Termination Messages can be sent by It should be noted that Session Termination Messages can be sent by
both routers and modems. both routers and modems.
9.10. Session Termination Response Message 10.10. Session Termination Response Message
A Session Termination Response Message MUST be sent by a DLEP A Session Termination Response Message MUST be sent by a DLEP
participant when a Session Termination Message (Section 9.9) is participant when a Session Termination Message (Section 10.9) is
received. received.
To construct a Session Termination Response Message, the Message Type To construct a Session Termination Response Message, the Message Type
value in the Message Header is set to 6, from Table 2. value in the Message Header is set to 6 (see Message Type
Registration (Section 13.3)).
There are no valid Data Items for the Session Termination Response There are no valid Data Items for the Session Termination Response
Message. Message.
Receipt of a Session Termination Response Message completes the tear- Receipt of a Session Termination Response Message completes the tear-
down of the DLEP session, see Section 4.4. down of the DLEP session, see Section 5.4.
9.11. Destination Up Message 10.11. Destination Up Message
Destination Up Messages MAY be sent by a modem to inform its attached Destination Up Messages MAY be sent by a modem to inform its attached
router of the presence of a new reachable destination. router of the presence of a new reachable destination.
To construct a Destination Up Message, the Message Type value in the To construct a Destination Up Message, the Message Type value in the
Message Header is set to 7, from Table 2. Message Header is set to 7 (see Message Type Registration
(Section 13.3)).
The Destination Up Message MUST contain a MAC Address Data Item The Destination Up Message MUST contain a MAC Address Data Item
(Section 10.7). (Section 11.7).
The Destination Up Message SHOULD contain one or more of each of the The Destination Up Message SHOULD contain one or more of each of the
following Data Items, with different values: following Data Items, with different values:
o IPv4 Address (Section 10.8) o IPv4 Address (Section 11.8)
o IPv6 Address (Section 10.9) o IPv6 Address (Section 11.9)
The Destination Up Message 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 10.12) o Maximum Data Rate (Receive) (Section 11.12)
o Maximum Data Rate (Transmit) (Section 10.13) o Maximum Data Rate (Transmit) (Section 11.13)
o Current Data Rate (Receive) (Section 10.14) o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 10.16) o Latency (Section 11.16)
The Destination Up Message MAY contain one of each of the following The Destination Up Message MAY contain one of each of the following
Data Items, if the Data Item is in use by the session: Data Items, if the Data Item is in use by the session:
o Resources (Section 10.17) o Resources (Section 11.17)
o Relative Link Quality (Receive) (Section 10.18) o Relative Link Quality (Receive) (Section 11.18)
o Relative Link Quality (Transmit) (Section 10.19) o Relative Link Quality (Transmit) (Section 11.19)
o Maximum Transmission Unit (MTU) (Section 10.20) o Maximum Transmission Unit (MTU) (Section 11.20)
The Destination Up Message MAY contain one or more of each of the The Destination Up Message MAY contain one or more of each of the
following Data Items, with different values: following Data Items, with different values:
o IPv4 Attached Subnet (Section 10.10) o IPv4 Attached Subnet (Section 11.10)
o IPv6 Attached Subnet (Section 11.11)
o IPv6 Attached Subnet (Section 10.11)
A router receiving a Destination Up Message allocates the necessary A router receiving a Destination Up Message allocates the necessary
resources, creating an entry in the information base with the resources, creating an entry in the information base with the
specifics (MAC Address, Latency, Data Rate, etc.) of the destination. specifics (MAC Address, Latency, Data Rate, etc.) of the destination.
The information about this destination will persist in the router's The information about this destination will persist in the router's
information base until a Destination Down Message (Section 9.15) is information base until a Destination Down Message (Section 10.15) is
received, indicating that the modem has lost contact with the remote received, indicating that the modem has lost contact with the remote
node, or the implementation transitions to the Session Termination node, or the implementation transitions to the Session Termination
state. state.
9.12. Destination Up Response Message 10.12. Destination Up Response Message
A router MUST send a Destination Up Response Message when a A router MUST send a Destination Up Response Message when a
Destination Up Message (Section 9.11) is received. Destination Up Message (Section 10.11) is received.
To construct a Destination Up Response Message, the Message Type To construct a Destination Up Response Message, the Message Type
value in the Message Header is set to 8, from Table 2. value in the Message Header is set to 8 (see Message Type
Registration (Section 13.3)).
The Destination Up Response Message 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 10.7) o MAC Address (Section 11.7)
o Status (Section 10.1) o Status (Section 11.1)
A router that wishes to receive further information concerning the A router that wishes to receive further information concerning the
destination identified in the corresponding Destination Up Message destination identified in the corresponding Destination Up Message
MUST set the status code of the included Status Data Item to 0 MUST set the status code of the included Status Data Item to 0
'Success', see Table 4. 'Success', see Table 2.
If the router has no interest in the destination identified in the If the router has no interest in the destination identified in the
corresponding Destination Up Message, then it MAY set the status code corresponding Destination Up Message, then it MAY set the status code
of the included Status Data Item to 1 'Not Interested'. of the included Status Data Item to 1 'Not Interested'.
A modem receiving a Destination Up Response Message containing a A modem receiving a Destination Up Response Message containing a
Status Data Item with status code of any value other than 0 'Success' Status Data Item with status code of any value other than 0 'Success'
MUST NOT send further Destination messages about the destination, MUST NOT send further Destination messages about the destination,
e.g. Destination Down (Section 9.15) or Destination Update e.g. Destination Down (Section 10.15) or Destination Update
(Section 9.17) with the same MAC address. (Section 10.17) with the same MAC address.
9.13. Destination Announce Message 10.13. Destination Announce Message
Usually a modem will discover the presence of one or more remote Usually a modem will discover the presence of one or more remote
router/modem pairs and announce each destination's arrival by sending router/modem pairs and announce each destination's arrival by sending
a corresponding Destination Up Message (Section 9.11) to the router. a corresponding Destination Up Message (Section 10.11) to the router.
However, there may be times when a router wishes to express an However, there may be times when a router wishes to express an
interest in a destination that has yet to be announced, typically a interest in a destination that has yet to be announced, typically a
multicast destination. Destination Announce Messages MAY be sent by multicast destination. Destination Announce Messages MAY be sent by
a router to announce such an interest. a router to announce such an interest.
A Destination Announce Message MAY also be sent by a router to A Destination Announce Message MAY also be sent by a router to
request information concerning a destination in which it has request information concerning a destination in which it has
previously declined interest, via the 1 'Not Interested' status code previously declined interest, via the 1 'Not Interested' status code
in a Destination Up Response Message (Section 9.12), see Table 4, or in a Destination Up Response Message (Section 10.12), see Table 2, or
declared as 'down', via the Destination Down Message (Section 9.15). declared as 'down', via the Destination Down Message (Section 10.15).
To construct a Destination Announce Message, the Message Type value To construct a Destination Announce Message, the Message Type value
in the Message Header is set to 9, from Table 2. in the Message Header is set to 9 (see Message Type Registration
(Section 13.3)).
The Destination Announce Message MUST contain a MAC Address Data Item The Destination Announce Message MUST contain a MAC Address Data Item
(Section 10.7). (Section 11.7).
The Destination Announce Message MAY contain zero or more of the The Destination Announce Message MAY contain zero or more of the
following Data Items, with different values: following Data Items, with different values:
o IPv4 Address (Section 10.8) o IPv4 Address (Section 11.8)
o IPv6 Address (Section 10.9) o IPv6 Address (Section 11.9)
One of the advantages of implementing DLEP is to leverage the modem's One of the advantages of implementing DLEP is to leverage the modem's
knowledge of the links between remote destinations allowing routers knowledge of the links between remote destinations allowing routers
to avoid using probed neighbor discovery techniques, therefore modem to avoid using probed neighbor discovery techniques, therefore modem
implementations SHOULD announce available destinations via the implementations SHOULD announce available destinations via the
Destination Up Message, rather than relying on Destination Announce Destination Up Message, rather than relying on Destination Announce
Messages. Messages.
9.14. Destination Announce Response Message 10.14. Destination Announce Response Message
A modem MUST send a Destination Announce Response Message when a A modem MUST send a Destination Announce Response Message when a
Destination Announce Message (Section 9.13) is received. Destination Announce Message (Section 10.13) is received.
To construct a Destination Announce Response Message, the Message To construct a Destination Announce Response Message, the Message
Type value in the Message Header is set to 10, from Table 2. Type value in the Message Header is set to 10 (see Message Type
Registration (Section 13.3)).
The Destination Announce Response Message MUST contain one of each of The Destination Announce Response Message MUST contain one of each of
the following Data Items: the following Data Items:
o MAC Address (Section 10.7) o MAC Address (Section 11.7)
o Status (Section 10.1) o Status (Section 11.1)
The Destination Announce Response Message MAY contain one or more of
each of the following Data Items, with different values:
o IPv4 Address (Section 11.8)
o IPv6 Address (Section 11.9)
o IPv4 Attached Subnet (Section 11.10)
o IPv6 Attached Subnet (Section 11.11)
The Destination Announce Response Message MAY contain one of each of The Destination Announce Response Message MAY contain one of each of
the following Data Items: the following Data Items:
o Maximum Data Rate (Receive) (Section 10.12) o Maximum Data Rate (Receive) (Section 11.12)
o Maximum Data Rate (Transmit) (Section 10.13) o Maximum Data Rate (Transmit) (Section 11.13)
o Current Data Rate (Receive) (Section 10.14) o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 10.16) o Latency (Section 11.16)
The Destination Announce Response Message MAY contain one of each of The Destination Announce Response Message MAY contain one of each of
the following Data Items, if the Data Item is in use by the session: the following Data Items, if the Data Item is in use by the session:
o Resources (Section 10.17) o Resources (Section 11.17)
o Relative Link Quality (Receive) (Section 10.18) o Relative Link Quality (Receive) (Section 11.18)
o Relative Link Quality (Transmit) (Section 10.19) o Relative Link Quality (Transmit) (Section 11.19)
o Maximum Transmission Unit (MTU) (Section 10.20) o Maximum Transmission Unit (MTU) (Section 11.20)
If a modem is unable to report information immediately about the If a modem is unable to report information immediately about the
requested information, if the destination is not currently reachable, requested information, if the destination is not currently reachable,
for example, the status code in the Status Data Item MUST be set to 2 for example, the status code in the Status Data Item MUST be set to 2
'Request Denied', see Table 4. 'Request Denied', see Table 2.
After sending a Destination Announce Response Message containing a After sending a Destination Announce Response Message containing a
Status Data Item with status code of 0 'Success', a modem then Status Data Item with status code of 0 'Success', a modem then
announces changes to the link to the destination via Destination announces changes to the link to the destination via Destination
Update Messages. Update Messages.
When a successful Destination Announce Response Message is received, When a successful Destination Announce Response Message is received,
the router should add knowledge of the available destination to its the router should add knowledge of the available destination to its
information base. information base.
9.15. Destination Down Message 10.15. Destination Down Message
A modem MUST send a Destination Down Message to report when a A modem 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. reachable.
A router MAY send a Destination Down Message to report when it no A router MAY send a Destination Down Message to report when it no
longer requires information concerning a destination. longer requires information concerning a destination.
To construct a Destination Down Message, the Message Type value in To construct a Destination Down Message, the Message Type value in
the Message Header is set to 11, from Table 2. the Message Header is set to 11 (see Message Type Registration
(Section 13.3)).
The Destination Down Message MUST contain a MAC Address Data Item The Destination Down Message MUST contain a MAC Address Data Item
(Section 10.7). (Section 11.7).
It should be noted that both modem and router may send a Destination It should be noted that both modem and router may send a Destination
Down Message to their peer, regardless of which participant initially Down Message to their peer, regardless of which participant initially
indicated the destination to be 'up'. indicated the destination to be 'up'.
9.16. Destination Down Response Message 10.16. Destination Down Response Message
A Destination Down Response MUST be sent by the recipient of a A Destination Down Response MUST be sent by the recipient of a
Destination Down Message (Section 9.15) to confirm that the relevant Destination Down Message (Section 10.15) to confirm that the relevant
data concerning the destination has been removed from the information data concerning the destination has been removed from the information
base. base.
To construct a Destination Down Response Message, the Message Type To construct a Destination Down Response Message, the Message Type
value in the Message Header is set to 12, from Table 2. value in the Message Header is set to 12 (see Message Type
Registration (Section 13.3)).
The Destination Down Response Message 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 10.7) o MAC Address (Section 11.7)
o Status (Section 10.1) o Status (Section 11.1)
9.17. Destination Update Message 10.17. Destination Update Message
A modem SHOULD send the Destination Update Message when it detects A modem SHOULD send the Destination Update Message when it detects
some change in the information base for a given destination (remote some change in the information base for a given destination (remote
node or multicast group). Some examples of changes that would prompt node or multicast group). Some examples of changes that would prompt
a Destination Update Message are: 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 Message, the Message Type value in To construct a Destination Update Message, the Message Type value in
the Message Header is set to 13, from Table 2. the Message Header is set to 13 (see Message Type Registration
(Section 13.3)).
The Destination Update Message MUST contain a MAC Address Data Item The Destination Update Message MUST contain a MAC Address Data Item
(Section 10.7). (Section 11.7).
The Destination Update Message 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 10.12) o Maximum Data Rate (Receive) (Section 11.12)
o Maximum Data Rate (Transmit) (Section 10.13) o Maximum Data Rate (Transmit) (Section 11.13)
o Current Data Rate (Receive) (Section 10.14) o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 10.16) o Latency (Section 11.16)
The Destination Update Message MAY contain one of each of the The Destination Update Message MAY contain one of each of the
following Data Items, if the Data Item is in use by the session: following Data Items, if the Data Item is in use by the session:
o Resources (Section 10.17) o Resources (Section 11.17)
o Relative Link Quality (Receive) (Section 10.18) o Relative Link Quality (Receive) (Section 11.18)
o Relative Link Quality (Transmit) (Section 10.19) o Relative Link Quality (Transmit) (Section 11.19)
o Maximum Transmission Unit (MTU) (Section 10.20) o Maximum Transmission Unit (MTU) (Section 11.20)
The Destination Update Message MAY contain one or more of each of the The Destination Update Message MAY contain one or more of each of the
following Data Items, with different values: following Data Items, with different values:
o IPv4 Address (Section 10.8) o IPv4 Address (Section 11.8)
o IPv6 Address (Section 10.9) o IPv6 Address (Section 11.9)
o IPv4 Attached Subnet (Section 10.10) o IPv4 Attached Subnet (Section 11.10)
o IPv6 Attached Subnet (Section 10.11) o IPv6 Attached Subnet (Section 11.11)
If metrics are supplied with the Message (e.g., Resources), these If metrics are supplied with the Message (e.g., Resources), these
metrics are MUST be applied to all destinations identified in the metrics are MUST be applied to all destinations identified in the
Message. Note that this may overwrite metrics provided in a Message. Note that this may overwrite metrics provided in a
previously received Session or Destination Up Messages. previously received Session or Destination Up Messages.
It should be noted that this Message has no corresponding response. It should be noted that this Message has no corresponding response.
9.18. Link Characteristics Request Message 10.18. Link Characteristics Request Message
The Link Characteristics Request Message MAY be sent by a router to The Link Characteristics Request Message MAY be sent by a 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.
To construct a Link Characteristics Request Message, the Message Type To construct a Link Characteristics Request Message, the Message Type
value in the Message Header is set to 14, from Table 2. value in the Message Header is set to 14 (see Message Type
Registration (Section 13.3)).
The Link Characteristics Request Message MUST contain one of the The Link Characteristics Request Message MUST contain one of the
following Data Items: following Data Items:
o MAC Address (Section 10.7) o MAC Address (Section 11.7)
The Link Characteristics Request Message MUST contain at least one of The Link Characteristics Request Message MUST contain at least one of
each of the following Data Items: each of the following Data Items:
o Current Data Rate (Receive) (Section 10.14) o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 10.16) o Latency (Section 11.16)
The Link Characteristics Request Message 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 is currently allocated, a Latency Data Item to request that than is currently allocated, a Latency Data Item to request that
traffic delay on the link not exceed the specified value, or both. traffic delay on the link not exceed the specified value, or both.
The router sending a Link Characteristics Request Message should be The router sending a Link Characteristics Request Message should be
aware that a request may take an extended period of time to complete. aware that a request may take an extended period of time to complete.
9.19. Link Characteristics Response Message 10.19. Link Characteristics Response Message
A modem MUST send a Link Characteristics Response Message when a Link A modem MUST send a Link Characteristics Response Message when a Link
Characteristics Request Message (Section 9.18) is received. Characteristics Request Message (Section 10.18) is received.
To construct a Link Characteristics Response Message, the Message To construct a Link Characteristics Response Message, the Message
Type value in the Message Header is set to 15, from Table 2. Type value in the Message Header is set to 15 (see Message Type
Registration (Section 13.3)).
The Link Characteristics Response Message MUST contain one of each of The Link Characteristics Response Message MUST contain one of each of
the following Data Items: the following Data Items:
o MAC Address (Section 10.7) o MAC Address (Section 11.7)
o Status (Section 11.1)
o Status (Section 10.1)
The Link Characteristics Response Message SHOULD contain one of each The Link Characteristics Response Message SHOULD contain one of each
of the following Data Items: of the following Data Items:
o Maximum Data Rate (Receive) (Section 10.12) o Maximum Data Rate (Receive) (Section 11.12)
o Maximum Data Rate (Transmit) (Section 10.13) o Maximum Data Rate (Transmit) (Section 11.13)
o Current Data Rate (Receive) (Section 10.14) o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 10.16) o Latency (Section 11.16)
The Link Characteristics Response Message MAY contain one of each of The Link Characteristics Response Message MAY contain one of each of
the following Data Items, if the Data Item is in use by the session: the following Data Items, if the Data Item is in use by the session:
o Resources (Section 10.17) o Resources (Section 11.17)
o Relative Link Quality (Receive) (Section 10.18) o Relative Link Quality (Receive) (Section 11.18)
o Relative Link Quality (Transmit) (Section 10.19) o Relative Link Quality (Transmit) (Section 11.19)
o Maximum Transmission Unit (MTU) (Section 10.20) o Maximum Transmission Unit (MTU) (Section 11.20)
The Link Characteristics Response Message MUST contain a complete set The Link Characteristics Response Message MUST contain a complete set
of metric Data Items, referencing all metrics declared in the Session of metric Data Items, referencing all metrics declared in the Session
Initialization Response Message (Section 9.6). The values in the Initialization Response Message (Section 10.6). The values in the
metric Data Items in the Link Characteristics Response Message MUST metric Data Items in the Link Characteristics Response Message MUST
reflect the link characteristics after the request has been reflect the link characteristics after the request has been
processed. 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 the status code of the Status Data link in the manner requested, then the status code of the Status Data
Item MUST be set to 2 'Request Denied', see Table 4. Item MUST be set to 2 'Request Denied', see Table 2.
9.20. Heartbeat Message 10.20. Heartbeat Message
A Heartbeat Message MUST be sent by a DLEP participant every N A Heartbeat Message MUST be sent by a DLEP participant every N
milliseconds, where N is defined in the Heartbeat Interval Data Item milliseconds, where N is defined in the Heartbeat Interval Data Item
(Section 10.5) of the Session Initialization Message (Section 9.5) or (Section 11.5) of the Session Initialization Message (Section 10.5)
Session Initialization Response Message (Section 9.6). or Session Initialization Response Message (Section 10.6).
To construct a Heartbeat Message, the Message Type value in the To construct a Heartbeat Message, the Message Type value in the
Message Header is set to 16, from Table 2. Message Header is set to 16 (see Message Type Registration
(Section 13.3)).
There are no valid Data Items for the Heartbeat Message. There are no valid Data Items for the Heartbeat Message.
The Message is used by DLEP participants to detect when a DLEP The Message is used by DLEP participants to detect when a DLEP
session peer (either the modem or the router) is no longer session peer (either the modem or the router) is no longer
communicating, see Section 4.3.1. communicating, see Section 5.3.1.
10. DLEP Data Items 11. DLEP Data Items
Following is the list of core Data Items that MUST be recognized by a Following is the list of core Data Items that MUST be recognized by a
DLEP compliant implementation. As mentioned before, not all Data DLEP compliant implementation. As mentioned before, not all Data
Items need be used during a session, but an implementation MUST Items need be used during a session, but an implementation MUST
correctly process these Data Items when correctly associated with a correctly process these Data Items when correctly associated with a
Signal or Message. Signal or Message.
The core DLEP Data Items are: The core DLEP Data Items are:
+-------------+-----------------------------------------------------+ +--------------------+----------------------------------------------+
| Type Code | Description | | Type Code | Description |
+-------------+-----------------------------------------------------+ +--------------------+----------------------------------------------+
| 0 | Reserved | | 0 | Reserved |
| 1 | Status (Section 10.1) | | 1 | Status (Section 11.1) |
| 2 | IPv4 Connection Point (Section 10.2) | | 2 | IPv4 Connection Point (Section 11.2) |
| 3 | IPv6 Connection Point (Section 10.3) | | 3 | IPv6 Connection Point (Section 11.3) |
| 4 | Peer Type (Section 10.4) | | 4 | Peer Type (Section 11.4) |
| 5 | Heartbeat Interval (Section 10.5) | | 5 | Heartbeat Interval (Section 11.5) |
| 6 | Extensions Supported (Section 10.6) | | 6 | Extensions Supported (Section 11.6) |
| 7 | MAC Address (Section 10.7) | | 7 | MAC Address (Section 11.7) |
| 8 | IPv4 Address (Section 10.8) | | 8 | IPv4 Address (Section 11.8) |
| 9 | IPv6 Address (Section 10.9) | | 9 | IPv6 Address (Section 11.9) |
| 10 | IPv4 Attached Subnet (Section 10.10) | | 10 | IPv4 Attached Subnet (Section 11.10) |
| 11 | IPv6 Attached Subnet (Section 10.11) | | 11 | IPv6 Attached Subnet (Section 11.11) |
| 12 | Maximum Data Rate (Receive) (MDRR) (Section 10.12) | | 12 | Maximum Data Rate (Receive) (MDRR) (Section |
| 13 | Maximum Data Rate (Transmit) (MDRT) (Section 10.13) | | | 11.12) |
| 14 | Current Data Rate (Receive) (CDRR) (Section 10.14) | | 13 | Maximum Data Rate (Transmit) (MDRT) (Section |
| 15 | Current Data Rate (Transmit) (CDRT) (Section 10.15) | | | 11.13) |
| 16 | Latency (Section 10.16) | | 14 | Current Data Rate (Receive) (CDRR) (Section |
| 17 | Resources (RES) (Section 10.17) | | | 11.14) |
| 18 | Relative Link Quality (Receive) (RLQR) (Section | | 15 | Current Data Rate (Transmit) (CDRT) (Section |
| | 10.18) | | | 11.15) |
| 19 | Relative Link Quality (Transmit) (RLQT) (Section | | 16 | Latency (Section 11.16) |
| | 10.19) | | 17 | Resources (RES) (Section 11.17) |
| 20 | Maximum Transmission Unit (MTU) (Section 10.20) | | 18 | Relative Link Quality (Receive) (RLQR) |
| 21-65407 | Reserved for future extensions | | | (Section 11.18) |
| 65408-65534 | Private Use. Available for experiments | | 19 | Relative Link Quality (Transmit) (RLQT) |
| 65535 | Reserved | | | (Section 11.19) |
+-------------+-----------------------------------------------------+ | 20 | Maximum Transmission Unit (MTU) (Section |
| | 11.20) |
| 21-65407 | Reserved for future extensions |
| 65408-65534 | Private Use. Available for experiments |
| 65535 | Reserved |
+--------------------+----------------------------------------------+
Table 3: DLEP Data Item types Table 1: DLEP Data Item types
10.1. Status 11.1. Status
For the Session Termination Message (Section 9.9), the Status Data For the Session Termination Message (Section 10.9), the Status Data
Item indicates a reason for the termination. For all response Item indicates a reason for the termination. For all response
Messages, the Status Data Item is used to indicate the success or Messages, the Status Data Item is used to indicate the success or
failure of the previously received Message. failure of the previously received Message.
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, e.g., it could field is entirely up to the receiving implementation, e.g., 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.
skipping to change at page 36, line 32 skipping to change at page 35, line 37
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Code | Text... : | Code | Text... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 1 Data Item Type: 1
Length: 1 + Length of text, in octets Length: 1 + Length of text, in octets
Status Code: One of the codes defined in Table 4 below. Status Code: One of the codes defined in Table 2 below.
Text: UTF-8 encoded string of UNICODE [UNIV8] characters, describing Text: UTF-8 encoded string of UNICODE [UNIV8] characters, describing
the cause, used for implementation defined purposes. Since this the cause, used for implementation defined purposes. Since this
field is used for description, implementations SHOULD limit field is used for description, implementations SHOULD limit
characters in this field to printable characters. Implementations characters in this field to printable characters. Implementations
receiving this Data Item SHOULD check for printable characters in receiving this Data Item SHOULD check for printable characters in
the field. 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 | Failure | Description | Reason | | Status | Failure | Description | Reason |
| Code | Mode | | | | Code | Mode | | |
+----------+-------------+------------------+-----------------------+ +---------+-----------+---------------+-----------------------------+
| 0 | Continue | Success | The Message was | | 0 | Continue | Success | The Message was processed |
| | | | processed | | | | | successfully. |
| | | | successfully. | | 1 | Continue | Not | The receiver is not |
| 1 | Continue | Not Interested | The receiver is not | | | | Interested | interested in this Message |
| | | | interested in this | | | | | subject, e.g. in a |
| | | | Message subject, e.g. | | | | | Destination Up Response |
| | | | in a Destination Up | | | | | Message (Section 10.12) to |
| | | | Response Message | | | | | indicate no further |
| | | | (Section 9.12) to | | | | | Messages about the |
| | | | indicate no further | | | | | destination. |
| | | | Messages about the | | 2 | Continue | Request | The receiver refuses to |
| | | | destination. | | | | Denied | complete the request. |
| 2 | Continue | Request Denied | The receiver refuses | | 3-111 | Continue | <Reserved> | Reserved for future |
| | | | to complete the | | | | | extensions. |
| | | | request. | | 112-127 | Continue | <Private Use> | Available for experiments. |
| 3-111 | Continue | <Reserved> | Reserved for future | | 128 | Terminate | Unknown | The Message was not |
| | | | extensions. | | | | Message | recognized by the |
| 112-127 | Continue | <Private Use> | Available for | | | | | implementation. |
| | | | experiments. | | 129 | Terminate | Unexpected | The Message was not |
| 128 | Terminate | Unknown Message | The Message was not | | | | Message | expected while the device |
| | | | recognized by the | | | | | was in the current state, |
| | | | implementation. | | | | | e.g., a Session |
| 129 | Terminate | Unexpected | The Message was not | | | | | Initialization Message |
| | | Message | expected while the | | | | | (Section 10.5) in the In- |
| | | | device was in the | | | | | Session state. |
| | | | current state, e.g., | | 130 | Terminate | Invalid Data | One or more Data Items in |
| | | | a Session | | | | | the Message are invalid, |
| | | | Initialization | | | | | unexpected or incorrectly |
| | | | Message (Section 9.5) | | | | | duplicated. |
| | | | in the In-Session | | 131 | Terminate | Invalid | The destination included in |
| | | | state. | | | | Destination | the Message does not match |
| 130 | Terminate | Invalid Data | One or more Data | | | | | a previously announced |
| | | | Items in the Message | | | | | destination. For example, |
| | | | are invalid, | | | | | in the Link Characteristic |
| | | | unexpected or | | | | | Response Message (Section |
| | | | incorrectly | | | | | 10.19). |
| | | | duplicated. | | 132 | Terminate | Timed Out | The session has timed out. |
| 131 | Terminate | Invalid | The destination | | 133 | Terminate | Invalid TTL | Message received with a TTL |
| | | Destination | included in the | | | | | other than 255. |
| | | | Message does not | | 134-239 | Terminate | <Reserved> | Reserved for future |
| | | | match a previously | | | | | extensions. |
| | | | announced | | 240-254 | Terminate | <Private Use> | Available for experiments. |
| | | | destination. For | | 255 | Terminate | <Reserved> | Reserved. |
| | | | example, in the Link | +---------+-----------+---------------+-----------------------------+
| | | | Characteristic |
| | | | Response Message |
| | | | (Section 9.19). |
| 132 | Terminate | Timed Out | The session has timed |
| | | | out. |
| 133-239 | Terminate | <Reserved> | Reserved for future |
| | | | extensions. |
| 240-254 | Terminate | <Private Use> | Available for |
| | | | experiments. |
| 255 | Terminate | <Reserved> | Reserved. |
+----------+-------------+------------------+-----------------------+
Table 4: DLEP Status Codes Table 2: DLEP Status Codes
10.2. IPv4 Connection Point 11.2. IPv4 Connection Point
The IPv4 Connection Point Data Item indicates the IPv4 address and, The IPv4 Connection Point Data Item indicates the IPv4 address and,
optionally, the TCP port number on the modem available for optionally, the TCP port number on the modem available for
connections. If provided, the router MUST use this information to connections. If provided, the router MUST use this information to
initiate the TCP connection to the modem. initiate the TCP connection to the modem.
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
skipping to change at page 38, line 40 skipping to change at page 37, line 37
Flags: Flags field, defined below. Flags: Flags field, defined below.
IPv4 Address: The IPv4 address listening on the modem. IPv4 Address: The IPv4 address listening on the modem.
TCP Port Number: TCP Port number on the modem. TCP Port Number: TCP Port number on the modem.
If the Length field is 7, the port number specified MUST be used to If the Length field is 7, 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 5, the router MUST use the DLEP well-known port the Length field is 5, the router MUST use the DLEP well-known port
number (Section 12.7) to establish the TCP connection. number (Section 13.7) to establish the TCP connection.
The Flags field is defined as: The Flags field is defined as:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved | | Reserved |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Reserved: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
10.3. IPv6 Connection Point 11.3. IPv6 Connection Point
The IPv6 Connection Point Data Item indicates the IPv6 address and, The IPv6 Connection Point Data Item indicates the IPv6 address and,
optionally, the TCP port number on the modem available for optionally, the TCP port number on the modem available for
connections. If provided, the router MUST use this information to connections. If provided, the router MUST use this information to
initiate the TCP connection to the modem. initiate the TCP connection to the modem.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 39, line 43 skipping to change at page 38, line 40
Flags: Flags field, defined below. Flags: Flags field, defined below.
IPv6 Address: The IPv6 address listening on the modem. IPv6 Address: The IPv6 address listening on the modem.
TCP Port Number: TCP Port number on the modem. TCP Port Number: TCP Port number on the modem.
If the Length field is 19, the port number specified MUST be used to If the Length field is 19, 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 17, the router MUST use the DLEP well-known port the Length field is 17, the router MUST use the DLEP well-known port
number (Section 12.7) to establish the TCP connection. number (Section 13.7) to establish the TCP connection.
The Flags field is defined as: The Flags field is defined as:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved | | Reserved |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Reserved: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
10.4. Peer Type 11.4. Peer Type
The Peer Type Data Item is used by the router and modem to give 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
skipping to change at page 40, line 37 skipping to change at page 39, line 36
Peer Type: UTF-8 encoded string of UNICODE [UNIV8] characters. For Peer Type: UTF-8 encoded string of UNICODE [UNIV8] characters. For
example, a satellite modem might set this variable to "Satellite example, a satellite modem might set this variable to "Satellite
terminal". Since this Data Item is intended to provide additional terminal". Since this Data Item is intended to provide additional
information for display commands, sending implementations SHOULD information for display commands, sending implementations SHOULD
limit the data to printable characters, and receiving limit the data to printable characters, and receiving
implementations SHOULD check the data for printable characters. implementations SHOULD check 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.
10.5. Heartbeat Interval 11.5. Heartbeat Interval
The Heartbeat Interval Data Item is used to specify a period in The Heartbeat Interval Data Item is used to specify a period in
milliseconds for Heartbeat Messages (Section 9.20). milliseconds for Heartbeat Messages (Section 10.20).
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 | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Heartbeat Interval | | Heartbeat Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 5
Data Item Type: 5
Length: 4 Length: 4
Heartbeat Interval: The interval in milliseconds, expressed as a Heartbeat Interval: The interval in milliseconds, expressed as a
32-bit unsigned integer, for Heartbeat Messages. This value MUST 32-bit unsigned integer, for Heartbeat Messages.
NOT be 0. This value MUST NOT be 0.
10.6. Extensions Supported 11.6. Extensions Supported
The Extensions Supported Data Item is used by the router and modem to The Extensions Supported Data Item is used by the router and modem to
negotiate additional optional functionality they are willing to negotiate additional optional functionality they are willing to
support. The Extensions List is a concatenation of the types of each support. The Extensions List is a concatenation of the types of each
supported extension, found in the IANA DLEP Extensions repository. supported extension, found in the IANA DLEP Extensions repository.
Each Extension Type definition includes which additional Signals and Each Extension Type definition includes which additional Signals and
Data Items are supported. Data Items are supported.
The Extensions Supported Data Item contains the following fields: The Extensions Supported Data Item contains the following fields:
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 6 Data Item Type: 6
Length: Length of the extensions list in octets. This is twice (2x) Length: Length of the extensions list in octets. This is twice (2x)
the number of extensions. the number of extensions.
Extension List: A list of extensions supported, identified by their Extension List: A list of extensions supported, identified by their
2-octet value as listed in the extensions registry. 2-octet value as listed in the extensions registry.
10.7. MAC Address 11.7. MAC Address
The MAC Address Data Item contains the address of the destination on The MAC Address Data Item contains the address of the destination on
the remote node. the remote node.
DLEP can support MAC addresses in either EUI-48 or EUI-64 format, DLEP can support MAC addresses in either EUI-48 or EUI-64 format,
with the restriction that all MAC addresses for a given DLEP session with the restriction that all MAC addresses for a given DLEP session
MUST be in the same format, and MUST be consistent with the MAC MUST be in the same format, and MUST be consistent with the MAC
address format of the connected modem (e.g., if the modem is address format of the connected modem (e.g., if the modem is
connected to the router with an EUI-48 MAC, all destination addresses connected to the router with an EUI-48 MAC, all destination addresses
via that modem MUST be expressed in EUI-48 format). via that modem MUST be expressed in EUI-48 format).
skipping to change at page 42, line 26 skipping to change at page 41, line 23
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: MAC Address : (if EUI-64 used) | : MAC Address : (if EUI-64 used) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 7 Data Item Type: 7
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.
10.8. IPv4 Address 11.8. IPv4 Address
When included in Destination Messages, this Data Item contains the When included in Destination Messages, this Data Item contains the
IPv4 address of the destination. When included in the Session Update IPv4 address of the destination. When included in the Session Update
Message, this Data Item contains the IPv4 address of the peer. In Message, this Data Item contains the IPv4 address of the peer. In
either case, the Data Item also contains an indication of whether 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 this is a new or existing address, or is a deletion of a previously
known address. known address.
The IPv4 Address Data Item contains the following fields: The IPv4 Address Data Item contains the following fields:
skipping to change at page 43, line 19 skipping to change at page 42, line 15
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing A: Add/Drop flag, indicating whether this is a new or existing
address (1), or a withdrawal of an address (0). address (1), or a withdrawal of an address (0).
Reserved: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
10.9. IPv6 Address 11.9. IPv6 Address
When included in Destination Messages, this Data Item contains the When included in Destination Messages, this Data Item contains the
IPv6 address of the destination. When included in the Session Update IPv6 address of the destination. When included in the Session Update
Message, this Data Item contains the IPv6 address of the peer. In Message, this Data Item contains the IPv6 address of the peer. In
either case, the Data Item also contains an indication of whether 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 this is a new or existing address, or is a deletion of a previously
known address. known address.
The IPv6 Address Data Item contains the following fields: The IPv6 Address Data Item contains the following fields:
skipping to change at page 44, line 17 skipping to change at page 43, line 15
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing A: Add/Drop flag, indicating whether this is a new or existing
address (1), or a withdrawal of an address (0). address (1), or a withdrawal of an address (0).
Reserved: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
10.10. IPv4 Attached Subnet 11.10. 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, that it has become an IPv4 subnet (e.g., a stub network) attached, that it has become
aware of an IPv4 subnet being present at a remote destination, or aware of an IPv4 subnet being present at a remote destination, or
that it has become aware of the loss of a subnet at the remote that it has become aware of the loss of a subnet at the remote
destination. destination.
The DLEP IPv4 Attached Subnet Data Item contains the following The DLEP IPv4 Attached Subnet Data Item contains the following
fields: fields:
skipping to change at page 45, line 15 skipping to change at page 44, line 15
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing subnet A: Add/Drop flag, indicating whether this is a new or existing subnet
address (1), or a withdrawal of a subnet address (0). address (1), or a withdrawal of a subnet address (0).
Reserved: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
10.11. IPv6 Attached Subnet 11.11. 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, that it has become an IPv6 subnet (e.g., a stub network) attached, that it has become
aware of an IPv6 subnet being present at a remote destination, or aware of an IPv6 subnet being present at a remote destination, or
that it has become aware of the loss of a subnet at the remote that it has become aware of the loss of a subnet at the remote
destination. destination.
The DLEP IPv6 Attached Subnet Data Item contains the following The DLEP IPv6 Attached Subnet Data Item contains the following
fields: fields:
skipping to change at page 46, line 17 skipping to change at page 45, line 17
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing subnet A: Add/Drop flag, indicating whether this is a new or existing subnet
address (1), or a withdrawal of a subnet address (0). address (1), or a withdrawal of a subnet address (0).
Reserved: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
10.12. Maximum Data Rate (Receive) 11.12. Maximum Data Rate (Receive)
The Maximum Data Rate (Receive) (MDRR) Data Item is used to indicate The Maximum Data Rate (Receive) (MDRR) Data Item is used to indicate
the maximum theoretical data rate, in bits per second, that can be the maximum theoretical data rate, in bits per second, that can be
achieved while receiving data on the link. 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
skipping to change at page 46, line 44 skipping to change at page 45, line 44
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 12 Data Item Type: 12
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.
10.13. Maximum Data Rate (Transmit) 11.13. Maximum Data Rate (Transmit)
The Maximum Data Rate (Transmit) (MDRT) Data Item is used to indicate The Maximum Data Rate (Transmit) (MDRT) Data Item is used to indicate
the maximum theoretical data rate, in bits per second, that can be the maximum theoretical data rate, in bits per second, that can be
achieved while transmitting data on the link. 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
skipping to change at page 47, line 23 skipping to change at page 46, line 23
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 13 Data Item Type: 13
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.
10.14. Current Data Rate (Receive) 11.14. Current Data Rate (Receive)
The Current Data Rate (Receive) (CDRR) Data Item is used to indicate The Current Data Rate (Receive) (CDRR) Data Item is used to indicate
the rate at which the link is currently operating for receiving the rate at which the link is currently operating for receiving
traffic. traffic.
When used in the Link Characteristics Request Message (Section 9.18), When used in the Link Characteristics Request Message
Current Data Rate (Receive) represents the desired receive rate, in (Section 10.18), Current Data Rate (Receive) represents the desired
bits per second, on the link. receive rate, in bits per second, on the 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 | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CDRR (bps) : | CDRR (bps) :
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Data Item Type: 14 Data Item Type: 14
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 Data Rate (Receive) and If there is no distinction between Current Data Rate (Receive) and
Maximum Data Rate (Receive) (Section 10.12), Current Data Rate Maximum Data Rate (Receive) (Section 11.12), Current Data Rate
(Receive) MUST be set equal to the Maximum Data Rate (Receive). The (Receive) MUST be set equal to the Maximum Data Rate (Receive). The
Current Data Rate (Receive) MUST NOT exceed the Maximum Data Rate Current Data Rate (Receive) MUST NOT exceed the Maximum Data Rate
(Receive). (Receive).
10.15. Current Data Rate (Transmit) 11.15. Current Data Rate (Transmit)
The Current Data Rate (Transmit) (CDRT) Data Item is used to indicate The Current Data Rate (Transmit) (CDRT) Data Item is used to indicate
the rate at which the link is currently operating for transmitting the rate at which the link is currently operating for transmitting
traffic. traffic.
When used in the Link Characteristics Request Message (Section 9.18), When used in the Link Characteristics Request Message
Current Data Rate (Transmit) represents the desired transmit rate, in (Section 10.18), Current Data Rate (Transmit) represents the desired
bits per second, on the link. transmit rate, in bits per second, on the 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 | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CDRT (bps) : | CDRT (bps) :
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Data Item Type: 15 Data Item Type: 15
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 Data Rate (Transmit) and If there is no distinction between Current Data Rate (Transmit) and
Maximum Data Rate (Transmit) (Section 10.13), Current Data Rate Maximum Data Rate (Transmit) (Section 11.13), Current Data Rate
(Transmit) MUST be set equal to the Maximum Data Rate (Transmit). (Transmit) MUST be set equal to the Maximum Data Rate (Transmit).
The Current Data Rate (Transmit) MUST NOT exceed the Maximum Data The Current Data Rate (Transmit) MUST NOT exceed the Maximum Data
Rate (Transmit). Rate (Transmit).
10.16. Latency 11.16. Latency
The Latency Data Item is used to indicate the amount of latency, in The Latency Data Item is used to indicate the amount of latency, in
microseconds, on the link. microseconds, on the link.
The Latency value is reported as transmission delay. The calculation The Latency value is reported as transmission delay. The calculation
of latency is implementation dependent. For example, the latency may of latency is implementation dependent. For example, the latency may
be a running average calculated from the internal queuing. be a running average calculated from the internal queuing.
The Latency Data Item contains the following fields: The Latency Data Item contains the following fields:
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 16 Data Item Type: 16
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.
10.17. Resources 11.17. Resources
The Resources (RES) Data Item is used to indicate the amount of The Resources (RES) Data Item is used to indicate the amount of
finite resources available for data transmission and reception at the finite resources available for data transmission and reception at the
destination as a percentage, with 0 meaning 'no resources remaining', destination as a percentage, with 0 meaning 'no resources remaining',
and 100 meaning 'a full supply', assuming that when Resources reaches and 100 meaning 'a full supply', assuming that when Resources reaches
0 data transmission and/or reception will cease. 0 data transmission and/or reception will cease.
An example of such resources might be battery life, but could equally An example of such resources might be battery life, but could equally
be magic beans. The list of resources that might be considered is be magic beans. The list of resources that might be considered is
beyond the scope of this document, and is left to implementations to beyond the scope of this document, and is left to implementations to
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Length: 1 Length: 1
Resources: An 8-bit unsigned integer percentage, 0-100, representing Resources: An 8-bit unsigned integer percentage, 0-100, representing
the amount of resources available. Any value greater than 100 the amount of resources available. Any value greater than 100
MUST be considered as invalid. MUST be considered as invalid.
If a device cannot calculate Resources, this Data Item MUST NOT be If a device cannot calculate Resources, this Data Item MUST NOT be
issued. issued.
10.18. Relative Link Quality (Receive) 11.18. Relative Link Quality (Receive)
The Relative Link Quality (Receive) (RLQR) Data Item is used to The Relative Link Quality (Receive) (RLQR) Data Item is used to
indicate the quality of the link to a destination for receiving indicate the quality of the link to a destination for receiving
traffic, with 0 meaning 'worst quality', and 100 meaning 'best traffic, with 0 meaning 'worst quality', and 100 meaning 'best
quality'. quality'.
Quality in this context is defined as an indication of the stability Quality in this context is defined as an indication of the stability
of a link for reception; a destination with high Relative Link of a link for reception; a destination with high Relative Link
Quality (Receive) is expected to have generally stable DLEP metrics, Quality (Receive) is expected to have generally stable DLEP metrics,
and the metrics of a destination with low Relative Link Quality and the metrics of a destination with low Relative Link Quality
skipping to change at page 51, line 7 skipping to change at page 50, line 7
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RLQR | | RLQR |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Data Item Type: 18 Data Item Type: 18
Length: 1 Length: 1
Relative Link Quality (Receive): A non-dimensional unsigned 8-bit Relative Link Quality (Receive): A non-dimensional unsigned 8-bit
integer, 0-100, representing relative quality of the link for integer, 0-100, representing relative quality of the link for
receiving traffic. Any value greater than 100 MUST be considered receiving traffic. Any value greater than 100 MUST be considered
as invalid. This is analogous to [RFC5578]. as invalid.
If a device cannot calculate the Relative Link Quality (Receive), If a device cannot calculate the Relative Link Quality (Receive),
this Data Item MUST NOT be issued. this Data Item MUST NOT be issued.
10.19. Relative Link Quality (Transmit) 11.19. Relative Link Quality (Transmit)
The Relative Link Quality (Transmit) (RLQT) Data Item is used to The Relative Link Quality (Transmit) (RLQT) Data Item is used to
indicate the quality of the link to a destination for transmitting indicate the quality of the link to a destination for transmitting
traffic, with 0 meaning 'worst quality', and 100 meaning 'best traffic, with 0 meaning 'worst quality', and 100 meaning 'best
quality'. quality'.
Quality in this context is defined as an indication of the stability Quality in this context is defined as an indication of the stability
of a link for transmission; a destination with high Relative Link of a link for transmission; a destination with high Relative Link
Quality (Transmit) is expected to have generally stable DLEP metrics, Quality (Transmit) is expected to have generally stable DLEP metrics,
and the metrics of a destination with low Relative Link Quality and the metrics of a destination with low Relative Link Quality
skipping to change at page 52, line 5 skipping to change at page 50, line 48
Length: 1 Length: 1
Relative Link Quality (Transmit): A non-dimensional unsigned 8-bit Relative Link Quality (Transmit): A non-dimensional unsigned 8-bit
integer, 0-100, representing relative quality of the link for integer, 0-100, representing relative quality of the link for
transmitting traffic. Any value greater than 100 MUST be transmitting traffic. Any value greater than 100 MUST be
considered as invalid. considered as invalid.
If a device cannot calculate the Relative Link Quality (Transmit), If a device cannot calculate the Relative Link Quality (Transmit),
this Data Item MUST NOT be issued. this Data Item MUST NOT be issued.
10.20. Maximum Transmission Unit (MTU) 11.20. Maximum Transmission Unit (MTU)
The Maximum Transmission Unit (MTU) Data Item is used to indicate the The Maximum Transmission Unit (MTU) Data Item is used to indicate the
maximum size, in octets, of an IP packet that can be transmitted maximum size, in octets, of an IP packet that can be transmitted
without fragmentation, including headers, but excluding any lower without fragmentation, including headers, but excluding any lower
layer headers. layer headers.
The Maximum Transmission Unit Data Item contains the following The Maximum Transmission Unit Data Item contains the following
fields: fields:
0 1 2 3 0 1 2 3
skipping to change at page 52, line 34 skipping to change at page 51, line 29
Length: 2 Length: 2
Maximum Transmission Unit: The maximum size, in octets, of an IP Maximum Transmission Unit: The maximum size, in octets, of an IP
packet that can be transmitted without fragmentation, including packet that can be transmitted without fragmentation, including
headers, but excluding any lower layer headers. headers, but excluding any lower layer headers.
If a device cannot calculate the Maximum Transmission Unit, this Data If a device cannot calculate the Maximum Transmission Unit, this Data
Item MUST NOT be issued. Item MUST NOT be issued.
11. Security Considerations 12. Security Considerations
The potential security concerns when using DLEP are: The potential security concerns when using DLEP are:
1. An attacker might pretend to be a DLEP participant, either at 1. An attacker might pretend to be a DLEP participant, either at
DLEP session initialization, or by injection of DLEP Messages DLEP session initialization, or by injection of DLEP Messages
once a session has been established, and/or once a session has been established, and/or
2. DLEP Data Items could be altered by an attacker, causing the 2. DLEP Data Items could be altered by an attacker, causing the
receiving implementation to inappropriately alter its information receiving implementation to inappropriately alter its information
base concerning network status. base concerning network status.
Since DLEP is restricted to operation over a single (possibly Since DLEP is restricted to operation over a single (possibly
logical) hop at layer 2, implementations requiring authentication logical) hop at layer 2, implementations requiring authentication and
and/or encryption of traffic MUST take steps to secure the Layer 2 /or encryption of traffic MUST take steps to secure the Layer 2 link.
link. Examples of technologies that can be deployed to secure the Examples of technologies that can be deployed to secure the Layer 2
Layer 2 link include [IEEE-802.1AE] and [IEEE-802.1X]. link include [IEEE-802.1AE] and [IEEE-802.1X].
To avoid potential denial of service attack, it is RECOMMENDED that To avoid potential denial of service attack, it is RECOMMENDED that
implementations using the Peer Discovery mechanism maintain an implementations using the Peer Discovery mechanism maintain an
information base of hosts that persistently fail Session information base of hosts that persistently fail Session
Initialization having provided an acceptable Peer Discovery Signal, Initialization having provided an acceptable Peer Discovery Signal,
and ignore subsequent Peer Discovery Signals from such hosts. and ignore subsequent Peer Discovery Signals from such hosts.
When using DLEP discovery, it is possible that an attacker who is not
in the layer 2 domain could successfully spoof a DLEP Discovery
signal, causing it to arrive at a mode with TTL=1. However, the
corresponding Peer Offer signal will also be sent with TTL=1, keeping
the Peer Offer from reaching the attacker. This attack can be
mitigated by using the information base described in the previous
paragraph to ignore subsequent attempts.
This specification does not address security of the data plane, as it This specification does not address security of the data plane, as it
(the data plane) is not affected, and standard security procedures (the data plane) is not affected, and standard security procedures
can be employed. can be employed.
12. IANA Considerations 13. IANA Considerations
This section specifies requests to IANA. This section specifies requests to IANA.
12.1. Registrations 13.1. Registrations
Upon approval of this document, IANA is requested to create a new Upon approval of this document, IANA is requested to create a new
protocol registry for Dynamic Link Exchange Protocol (DLEP). The protocol registry for Dynamic Link Exchange Protocol (DLEP). The
remainder of this section requests the creation of new DLEP specific remainder of this section requests the creation of new DLEP specific
registries. registries.
12.2. Signal Type Registration 13.2. Signal Type Registration
Upon approval of this document, IANA is requested to create a new Upon approval of this document, IANA is requested to create a new
DLEP registry, named "Signal Type Values". DLEP registry, named "Signal Type Values".
The following table provides initial registry values and the The following table provides initial registry values and the
[RFC5226] defined policies that should apply to the registry: [RFC5226] defined policies that should apply to the registry:
+--------------+-------------------------+ +--------------+-------------------------+
| Type Code | Description/Policy | | Type Code | Description/Policy |
+--------------+-------------------------+ +--------------+-------------------------+
| 0 | Reserved | | 0 | Reserved |
| 1 | Peer Discovery Signal | | 1 | Peer Discovery Signal |
| 2 | Peer Offer Signal | | 2 | Peer Offer Signal |
| 3-65519 | Specification Required | | 3-65519 | Specification Required |
| 65520-65534 | Private Use | | 65520-65534 | Private Use |
| 65535 | Reserved | | 65535 | Reserved |
+--------------+-------------------------+ +--------------+-------------------------+
12.3. Message Type Registration 13.3. Message Type Registration
Upon approval of this document, IANA is requested to create a new Upon approval of this document, IANA is requested to create a new
DLEP registry, named "Message Type Values". DLEP registry, named "Message Type Values".
The following table provides initial registry values and the The following table provides initial registry values and the
[RFC5226] defined policies that should apply to the registry: [RFC5226] defined policies that should apply to the registry:
+--------------+------------------------------------------+ +--------------+------------------------------------------+
| Type Code | Description/Policy | | Type Code | Description/Policy |
+--------------+------------------------------------------+ +--------------+------------------------------------------+
skipping to change at page 54, line 30 skipping to change at page 53, line 33
| 12 | Destination Down Response Message | | 12 | Destination Down Response Message |
| 13 | Destination Update Message | | 13 | Destination Update Message |
| 14 | Link Characteristics Request Message | | 14 | Link Characteristics Request Message |
| 15 | Link Characteristics Response Message | | 15 | Link Characteristics Response Message |
| 16 | Heartbeat Message | | 16 | Heartbeat Message |
| 17-65519 | Specification Required | | 17-65519 | Specification Required |
| 65520-65534 | Private Use | | 65520-65534 | Private Use |
| 65535 | Reserved | | 65535 | Reserved |
+--------------+------------------------------------------+ +--------------+------------------------------------------+
12.4. DLEP Data Item Registrations 13.4. DLEP Data Item Registrations
Upon approval of this document, IANA is requested to create a new Upon approval of this document, IANA is requested to create a new
DLEP registry, named "Data Item Values". DLEP registry, named "Data Item Values".
The following table provides initial registry values and the The following table provides initial registry values and the
[RFC5226] defined policies that should apply to the registry: [RFC5226] defined policies that should apply to the registry:
+-------------------+------------------------------------------+ +--------------+------------------------------------------+
| Type Code | Description/Policy | | Type Code | Description/Policy |
+-------------------+------------------------------------------+ +--------------+------------------------------------------+
| 0 | Reserved | | 0 | Reserved |
| 1 | Status | | 1 | Status |
| 2 | IPv4 Connection Point | | 2 | IPv4 Connection Point |
| 3 | IPv6 Connection Point | | 3 | IPv6 Connection Point |
| 4 | Peer Type | | 4 | Peer Type |
| 5 | Heartbeat Interval | | 5 | Heartbeat Interval |
| 6 | Extensions Supported | | 6 | Extensions Supported |
| 7 | MAC Address | | 7 | MAC Address |
| 8 | IPv4 Address | | 8 | IPv4 Address |
| 9 | IPv6 Address | | 9 | IPv6 Address |
| 10 | IPv4 Attached Subnet | | 10 | IPv4 Attached Subnet |
| 11 | IPv6 Attached Subnet | | 11 | IPv6 Attached Subnet |
| 12 | Maximum Data Rate (Receive) (MDRR) | | 12 | Maximum Data Rate (Receive) (MDRR) |
| 13 | Maximum Data Rate (Transmit) (MDRT) | | 13 | Maximum Data Rate (Transmit) (MDRT) |
| 14 | Current Data Rate (Receive) (CDRR) | | 14 | Current Data Rate (Receive) (CDRR) |
| 15 | Current Data Rate (Transmit) (CDRT) | | 15 | Current Data Rate (Transmit) (CDRT) |
| 16 | Latency | | 16 | Latency |
| 17 | Resources (RES) | | 17 | Resources (RES) |
| 18 | Relative Link Quality (Receive) (RLQR) | | 18 | Relative Link Quality (Receive) (RLQR) |
| 19 | Relative Link Quality (Transmit) (RLQT) | | 19 | Relative Link Quality (Transmit) (RLQT) |
| 20 | Maximum Transmission Unit (MTU) | | 20 | Maximum Transmission Unit (MTU) |
| 21-65407 | Specification Required | | 21-65407 | Specification Required |
| 65408-65534 | Private Use | | 65408-65534 | Private Use |
| 65535 | Reserved | | 65535 | Reserved |
+-------------------+------------------------------------------+ +--------------+------------------------------------------+
12.5. DLEP Status Code Registrations 13.5. DLEP Status Code Registrations
Upon approval of this document, IANA is requested to create a new Upon approval of this document, IANA is requested to create a new
DLEP registry, named "Status Code Values". DLEP registry, named "Status Code Values".
The following table provides initial registry values and the The following table provides initial registry values and the
[RFC5226] defined policies that should apply to the registry: [RFC5226] defined policies that should apply to the registry:
+--------------+---------------+-------------------------+ +--------------+---------------+-------------------------+
| Status Code | Failure Mode | Description/Policy | | Status Code | Failure Mode | Description/Policy |
+--------------+---------------+-------------------------+ +--------------+---------------+-------------------------+
skipping to change at page 56, line 23 skipping to change at page 55, line 5
| 128 | Terminate | Unknown Message | | 128 | Terminate | Unknown Message |
| 129 | Terminate | Unexpected Message | | 129 | Terminate | Unexpected Message |
| 130 | Terminate | Invalid Data | | 130 | Terminate | Invalid Data |
| 131 | Terminate | Invalid Destination | | 131 | Terminate | Invalid Destination |
| 132 | Terminate | Timed Out | | 132 | Terminate | Timed Out |
| 133-239 | Terminate | Specification Required | | 133-239 | Terminate | Specification Required |
| 240-254 | Terminate | Private Use | | 240-254 | Terminate | Private Use |
| 255 | Terminate | Reserved | | 255 | Terminate | Reserved |
+--------------+---------------+-------------------------+ +--------------+---------------+-------------------------+
12.6. DLEP Extensions Registrations 13.6. DLEP Extensions Registrations
Upon approval of this document, IANA is requested to create a new Upon approval of this document, IANA is requested to create a new
DLEP registry, named "Extension Type Values". DLEP registry, named "Extension Type Values".
The following table provides initial registry values and the The following table provides initial registry values and the
[RFC5226] defined policies that should apply to the registry: [RFC5226] defined policies that should apply to the registry:
+--------------+----------------------------+ +--------------+----------------------------+
| Code | Description/Policy | | Code | Description/Policy |
+--------------+----------------------------+ +--------------+----------------------------+
| 0 | Reserved | | 0 | Reserved |
| 1 | Credit Windowing [CREDIT] | | 1 | Credit Windowing [CREDIT] |
| 2-65519 | Specification Required | | 2-65519 | Specification Required |
| 65520-65534 | Private Use | | 65520-65534 | Private Use |
| 65535 | Reserved | | 65535 | Reserved |
+--------------+----------------------------+ +--------------+----------------------------+
Table 5: DLEP Extension types Table 3: DLEP Extension types
12.7. DLEP Well-known Port 13.7. DLEP Well-known Port
Upon approval of this document, IANA is requested to assign a single Upon approval of this document, IANA is requested to assign a single
value in the "Service Name and Transport Protocol Port Number value in the "Service Name and Transport Protocol Port Number
Registry" found at https://www.iana.org/assignments/service-names- Registry" found at https://www.iana.org/assignments/service-names-
port-numbers/service-names-port-numbers.xhtml for use by "DLEP", as port-numbers/service-names-port-numbers.xhtml for use by "DLEP", as
defined in this document. This assignment should be valid for TCP defined in this document. This assignment should be valid for TCP
and UDP. SCTP port allocation is not required. and UDP.
12.8. DLEP IPv4 Link-local Multicast Address 13.8. DLEP IPv4 Link-local Multicast Address
Upon approval of this document, IANA is requested to assign an IPv4 Upon approval of this document, IANA is requested to assign an IPv4
multicast address registry found at http://www.iana.org/assignments/ multicast address registry found at http://www.iana.org/assignments/
multicast-addresses for use as the "IPv4 DLEP Discovery Address". multicast-addresses for use as the "IPv4 DLEP Discovery Address".
12.9. DLEP IPv6 Link-local Multicast Address 13.9. DLEP IPv6 Link-local Multicast Address
Upon approval of this document, IANA is requested to assign an IPv6 Upon approval of this document, IANA is requested to assign an IPv6
multicast address registry found at http://www.iana.org/assignments/ multicast address registry found at http://www.iana.org/assignments/
multicast-addresses for use as the "IPv6 DLEP Discovery Address". multicast-addresses for use as the "IPv6 DLEP Discovery Address".
13. Acknowledgements 14. 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, Lou Berger, and Victoria Mercieca. Vikram Kaul, Nelson Powell, Lou Berger, and Victoria Mercieca.
14. References 15. References
14.1. Normative References
[CREDIT] Ratliff, S., "Credit Windowing extension for DLEP", IETF 15.1. Normative References
draft draft-ietf-manet-credit-window-04, March 2016.
[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, DOI 10.17487/ Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997, RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[UNIV8] "The Unicode Consortium. The Unicode Standard, Version [RFC5082] Gill, V., Heasley, J., Meyer, D., Savola, P., Ed., and C.
Pignataro, "The Generalized TTL Security Mechanism
(GTSM)", RFC 5082, DOI 10.17487/RFC5082, October 2007,
<http://www.rfc-editor.org/info/rfc5082>.
[UNIV8] , "The Unicode Consortium. The Unicode Standard, Version
8.0.0, (Mountain View, CA: The Unicode Consortium, 2015. 8.0.0, (Mountain View, CA: The Unicode Consortium, 2015.
ISBN 978-1-936213-10-8)", ISBN 978-1-936213-10-8)",
http://www.unicode.org/versions/Unicode8.0.0/, June 2015. http://www.unicode.org/versions/Unicode8.0.0/, June 2015.
14.2. Informative References 15.2. Informative References
[CREDIT] Ratliff, S., "Credit Windowing extension for DLEP", IETF
draft draft-ietf-manet-credit-window-04, March 2016.
[IEEE-802.1AE] [IEEE-802.1AE]
"IEEE Standards for Local and Metropolitan Area Networks: , "IEEE Standards for Local and Metropolitan Area
Media Access Control (MAC) Security", DOI 10.1109/ Networks: Media Access Control (MAC) Security", DOI
IEEESTD.2006.245590, August 2006. 10.1109/IEEESTD.2006.245590, August 2006.
[IEEE-802.1X] [IEEE-802.1X]
"IEEE Standards for Local and Metropolitan Area Networks: , "IEEE Standards for Local and Metropolitan Area
Port based Network Access Control", DOI 10.1109/ Networks: Port based Network Access Control", DOI 10.1109/
IEEESTD.2010.5409813, February 2010. IEEESTD.2010.5409813, February 2010.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008, DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>. <http://www.rfc-editor.org/info/rfc5226>.
[RFC5578] Berry, B., Ed., Ratliff, S., Paradise, E., Kaiser, T., and [RFC5578] Berry, B., Ed., Ratliff, S., Paradise, E., Kaiser, T., and
M. Adams, "PPP over Ethernet (PPPoE) Extensions for Credit M. Adams, "PPP over Ethernet (PPPoE) Extensions for Credit
Flow and Link Metrics", RFC 5578, DOI 10.17487/RFC5578, Flow and Link Metrics", RFC 5578, DOI 10.17487/RFC5578,
February 2010, <http://www.rfc-editor.org/info/rfc5578>. February 2010, <http://www.rfc-editor.org/info/rfc5578>.
Appendix A. Discovery Signal Flows Appendix A. Discovery Signal Flows
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---->X Signal. |-------Peer Discovery---->X Signal.
~ ~ ~ ~ ~ ~ ~ Router discovery timer expires ~ ~ ~ ~ ~ ~ ~ Router discovery timer expires
without receiving Peer Offer. without receiving Peer Offer.
| Router sends another Peer | Router sends another Peer
|-------Peer Discovery---------->| Discovery Signal. |-------Peer Discovery---------->| Discovery Signal.
| |
| 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.
Appendix B. Peer Level Message Flows Appendix B. Peer Level Message Flows
B.1. Session Initialization B.1. Session Initialization
Router Modem Message Description
========================================================================
| Router connects to discovered or Router Modem Message Description
| pre-configured Modem Connection ========================================================================
|--TCP connection established---> Point.
| | Router connects to discovered or
| Router sends Session | pre-configured Modem Connection
|----Session Initialization----->| Initialization Message. |--TCP connection established---> Point.
| |
| Modem receives Session | Router sends Session
| Initialization Message. |----Session Initialization----->| Initialization Message.
| |
| Modem sends Session Initialization | Modem receives Session
|<--Session Initialization Resp.-| Response, with Success Status Data | Initialization Message.
| | Item. |
| | | Modem sends Session Initialization
|<<============================>>| Session established. Heartbeats |<--Session Initialization Resp.-| Response, with Success Status Data
: : begin. | | Item.
| |
|<<============================>>| Session established. Heartbeats
: : begin.
B.2. Session Initialization - Refused B.2. Session Initialization - Refused
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
| Router connects to discovered or | Router connects to discovered or
| pre-configured Modem Connection | pre-configured Modem Connection
|--TCP connection established---> Point. |--TCP connection established---> Point.
| |
| Router sends Session | Router sends Session
|-----Session Initialization---->| Initialization Message. |-----Session Initialization---->| Initialization Message.
| |
| Modem receives Session | Modem receives Session
| Initialization Message, and will | Initialization Message, and will
| not support the advertised | not support the advertised
| extensions. | extensions.
| |
| Modem sends Session Initialization | Modem sends Session Initialization
| Response, with 'Request Denied' | Response, with 'Request Denied'
|<-Session Initialization Resp.--| Status Data Item. |<-Session Initialization Resp.--| Status Data Item.
| |
| |
| Router receives negative Session | Router receives negative Session
| Initialization Response, closes | Initialization Response, closes
||---------TCP close------------|| TCP connection. ||---------TCP close------------|| TCP connection.
B.3. Router Changes IP Addresses B.3. Router Changes IP Addresses
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
| Router sends Session Update | Router sends Session Update
|-------Session Update---------->| Message to announce change of IP |-------Session Update---------->| Message to announce change of IP
| address | address
| |
| Modem receives Session Update | Modem receives Session Update
| Message and updates internal | Message and updates internal
| state. | state.
| |
|<----Session Update Response----| Modem sends Session Update |<----Session Update Response----| Modem sends Session Update
| Response. | Response.
B.4. Modem Changes Session-wide Metrics B.4. Modem Changes Session-wide Metrics
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
| Modem sends Session Update Message | Modem sends Session Update Message
| to announce change of modem-wide | to announce change of modem-wide
|<--------Session Update---------| metrics |<--------Session Update---------| metrics
| |
| Router receives Session Update | Router receives Session Update
| Message and updates internal | Message and updates internal
| state. | state.
| |
|----Session Update Response---->| Router sends Session Update |----Session Update Response---->| Router sends Session Update
| Response. | Response.
B.5. Router Terminates Session B.5. Router Terminates Session
Router Modem Message Description
========================================================================
| Router sends Session Termination Router Modem Message Description
|------Session Termination------>| Message with Status Data Item. ========================================================================
| |
|-------TCP shutdown (send)---> | Router stops sending Messages. | Router sends Session Termination
| |------Session Termination------>| Message with Status Data Item.
| Modem receives Session | |
| Termination, stops counting |-------TCP shutdown (send)---> | Router stops sending Messages.
| received heartbeats and stops |
| sending heartbeats. | Modem receives Session
| | Termination, stops counting
| Modem sends Session Termination | received heartbeats and stops
|<---Session Termination Resp.---| Response with Status 'Success'. | sending heartbeats.
| |
| Modem stops sending Messages. | Modem sends Session Termination
| |<---Session Termination Resp.---| Response with Status 'Success'.
||---------TCP close------------|| Session terminated. |
| Modem stops sending Messages.
|
||---------TCP close------------|| Session terminated.
B.6. Modem Terminates Session B.6. Modem Terminates Session
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
| Modem sends Session Termination | Modem sends Session Termination
|<----Session Termination--------| Message with Status Data Item. |<----Session Termination--------| Message with Status Data Item.
| |
| Modem stops sending Messages. | Modem stops sending Messages.
| |
| Router receives Session | Router receives Session
| Termination, stops counting | Termination, stops counting
| received heartbeats and stops | received heartbeats and stops
| sending heartbeats. | sending heartbeats.
| |
| Router sends Session Termination | Router sends Session Termination
|---Session Termination Resp.--->| Response with Status 'Success'. |---Session Termination Resp.--->| Response with Status 'Success'.
| |
| Router stops sending Messages. | Router stops sending Messages.
| |
||---------TCP close------------|| Session terminated. ||---------TCP close------------|| Session terminated.
B.7. Session Heartbeats B.7. Session Heartbeats
Router Modem Message Description
========================================================================
|----------Heartbeat------------>| Router sends heartbeat Message Router Modem Message Description
| ========================================================================
| Modem resets heartbeats missed
| counter.
~ ~ ~ ~ ~ ~ ~ |----------Heartbeat------------>| Router sends heartbeat Message
|
| Modem resets heartbeats missed
| counter.
|---------[Any Message]--------->| When the Modem receives any ~ ~ ~ ~ ~ ~ ~
| Message from the Router.
|
| Modem resets heartbeats missed
| counter.
~ ~ ~ ~ ~ ~ ~ |---------[Any Message]--------->| When the Modem receives any
| Message from the Router.
|
| Modem resets heartbeats missed
| counter.
|<---------Heartbeat-------------| Modem sends heartbeat Message ~ ~ ~ ~ ~ ~ ~
|
| Router resets heartbeats missed
| counter.
~ ~ ~ ~ ~ ~ ~ |<---------Heartbeat-------------| Modem sends heartbeat Message
|
| Router resets heartbeats missed
| counter.
|<--------[Any Message]----------| When the Router receives any ~ ~ ~ ~ ~ ~ ~
| Message from the Modem.
| |<--------[Any Message]----------| When the Router receives any
| Modem resets heartbeats missed | Message from the Modem.
| counter. |
| Modem resets heartbeats missed
| counter.
B.8. Router Detects a Heartbeat timeout B.8. Router Detects a Heartbeat timeout
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
X<----------------------| Router misses a heartbeat X<----------------------| Router misses a heartbeat
| X<----------------------| Router misses too many heartbeats | X<----------------------| Router misses too many heartbeats
| |
| |
|------Session Termination------>| Router sends Session Termination |------Session Termination------>| Router sends Session Termination
| Message with 'Timeout' Status | Message with 'Timeout' Status
| Data Item. | Data Item.
: :
: Termination proceeds... : Termination proceeds...
B.9. Modem Detects a Heartbeat timeout B.9. Modem Detects a Heartbeat timeout
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
|---------------------->X Modem misses a heartbeat |---------------------->X Modem misses a heartbeat
|---------------------->X | Modem misses too many heartbeats |---------------------->X | Modem misses too many heartbeats
| |
| |
|<-----Session Termination-------| Modem sends Session Termination |<-----Session Termination-------| Modem sends Session Termination
| Message with 'Timeout' Status | Message with 'Timeout' Status
| Data Item. | Data Item.
: :
: Termination proceeds... : Termination proceeds...
Appendix C. Destination Specific Message Flows Appendix C. Destination Specific Message Flows
C.1. Common Destination Notification C.1. Common Destination Notification
Router Modem Message Description
========================================================================
| Modem detects a new logical Router Modem Message Description
| destination is reachable, and ========================================================================
|<-------Destination Up----------| sends Destination Up Message.
|
|------Destination Up Resp.----->| Router sends Destination Up
| Response.
~ ~ ~ ~ ~ ~ ~ | Modem detects a new logical
| Modem detects change in logical | destination is reachable, and
| destination metrics, and sends |<-------Destination Up----------| sends Destination Up Message.
|<-------Destination Update------| Destination Update Message. |
|------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 Message. |<-------Destination Update------| Destination Update Message.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects logical destination | Modem detects change in logical
| is no longer reachable, and sends | destination metrics, and sends
|<-------Destination Down--------| Destination Down Message. |<-------Destination Update------| Destination Update Message.
|
| Router receives Destination Down, ~ ~ ~ ~ ~ ~ ~
| updates internal state, and sends | Modem detects logical destination
|------Destination Down Resp.--->| Destination Down Response Message. | is no longer reachable, and sends
|<-------Destination Down--------| Destination Down Message.
|
| Router receives Destination Down,
| updates internal state, and sends
|------Destination Down Resp.--->| Destination Down Response Message.
C.2. Multicast Destination Notification C.2. Multicast Destination Notification
Router Modem Message Description
========================================================================
| Router detects a new multicast Router Modem Message Description
| destination is in use, and sends ========================================================================
|-----Destination Announce------>| Destination Announce Message.
|
| Modem updates internal state to
| monitor multicast destination, and
|<-----Dest. Announce Resp.------| sends Destination Announce
Response.
~ ~ ~ ~ ~ ~ ~ | Router detects a new multicast
| Modem detects change in multicast | destination is in use, and sends
| destination metrics, and sends |-----Destination Announce------>| Destination Announce Message.
|<-------Destination Update------| Destination Update Message. |
| Modem updates internal state to
| monitor multicast destination, and
|<-----Dest. Announce Resp.------| sends Destination Announce
Response.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects change in multicast | Modem detects change in multicast
| destination metrics, and sends | destination metrics, and sends
|<-------Destination Update------| Destination Update Message. |<-------Destination Update------| Destination Update Message.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Router detects multicast | Modem detects change in multicast
| destination is no longer in use, | destination metrics, and sends
|--------Destination Down------->| and sends Destination Down |<-------Destination Update------| Destination Update Message.
| Message.
| ~ ~ ~ ~ ~ ~ ~
| Modem receives Destination Down, | Router detects multicast
| updates internal state, and sends | destination is no longer in use,
|<-----Destination Down Resp.----| Destination Down Response Message. |--------Destination Down------->| and sends Destination Down
| Message.
|
| Modem receives Destination Down,
| updates internal state, and sends
|<-----Destination Down Resp.----| Destination Down Response Message.
C.3. Link Characteristics Request C.3. Link Characteristics Request
Router Modem Message Description
========================================================================
Destination has already been Router Modem Message Description
~ ~ ~ ~ ~ ~ ~ announced by either peer. ========================================================================
| Router requires different Destination has already been
| Characteristics for the ~ ~ ~ ~ ~ ~ ~ announced by either peer.
| destination, and sends Link
|--Link Characteristics Request->| Characteristics Request Message. | Router requires different
| | Characteristics for the
| Modem attempts to adjust link | destination, and sends Link
| properties to meet the received |--Link Characteristics Request->| Characteristics Request Message.
| request, and sends a Link |
| Characteristics Response | Modem attempts to adjust link
|<---Link Characteristics Resp.--| Message with the new values. | properties to meet the received
| request, and sends a Link
| Characteristics Response
|<---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
Bo Berry
Shawn Jury Shawn Jury
Cisco Systems Cisco Systems
170 West Tasman Drive 170 West Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
USA USA
Email: sjury@cisco.com Email: sjury@cisco.com
Darryl Satterwhite Darryl Satterwhite
Broadcom Broadcom
skipping to change at line 2967 skipping to change at page 64, line 13
Email: dsatterw@broadcom.com Email: dsatterw@broadcom.com
Rick Taylor Rick Taylor
Airbus Defence & Space Airbus Defence & Space
Quadrant House Quadrant House
Celtic Springs Celtic Springs
Coedkernew Coedkernew
Newport NP10 8FZ Newport NP10 8FZ
UK UK
Email: rick.taylor@airbus.com Email: rick.taylor@airbus.com
Bo Berry
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