< draft-ietf-roll-aodv-rpl-03.txt   draft-ietf-roll-aodv-rpl-04.txt >
ROLL S. Anamalamudi ROLL S. Anamalamudi
Internet-Draft Huaiyin Institute of Technology Internet-Draft SRM University-AP
Intended status: Standards Track M. Zhang Intended status: Standards Track M. Zhang
Expires: September 6, 2018 Huawei Technologies Expires: January 3, 2019 Huawei Technologies
AR. Sangi AR. Sangi
Huaiyin Institute of Technology Huaiyin Institute of Technology
C. Perkins C. Perkins
Futurewei Futurewei
S.V.R.Anand S.V.R.Anand
Indian Institute of Science Indian Institute of Science
B. Liu B. Liu
Huawei Technologies Huawei Technologies
March 5, 2018 July 2, 2018
Asymmetric AODV-P2P-RPL in Low-Power and Lossy Networks (LLNs) Asymmetric AODV-P2P-RPL in Low-Power and Lossy Networks (LLNs)
draft-ietf-roll-aodv-rpl-03 draft-ietf-roll-aodv-rpl-04
Abstract Abstract
Route discovery for symmetric and asymmetric Point-to-Point (P2P) Route discovery for symmetric and asymmetric Point-to-Point (P2P)
traffic flows is a desirable feature in Low power and Lossy Networks traffic flows is a desirable feature in Low power and Lossy Networks
(LLNs). For that purpose, this document specifies a reactive P2P (LLNs). For that purpose, this document specifies a reactive P2P
route discovery mechanism for both hop-by-hop routing and source route discovery mechanism for both hop-by-hop routing and source
routing: Ad Hoc On-demand Distance Vector Routing (AODV) based RPL routing: Ad Hoc On-demand Distance Vector Routing (AODV) based RPL
protocol. Paired Instances are used to construct directional paths, protocol. Paired Instances are used to construct directional paths,
in case some of the links between source and target node are in case some of the links between source and target node are
skipping to change at page 1, line 46 skipping to change at page 1, line 46
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This Internet-Draft will expire on September 6, 2018. This Internet-Draft will expire on January 3, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
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skipping to change at page 2, line 25 skipping to change at page 2, line 25
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Overview of AODV-RPL . . . . . . . . . . . . . . . . . . . . 6 3. Overview of AODV-RPL . . . . . . . . . . . . . . . . . . . . 6
4. AODV-RPL DIO Options . . . . . . . . . . . . . . . . . . . . 6 4. AODV-RPL DIO Options . . . . . . . . . . . . . . . . . . . . 7
4.1. AODV-RPL DIO RREQ Option . . . . . . . . . . . . . . . . 6 4.1. AODV-RPL DIO RREQ Option . . . . . . . . . . . . . . . . 7
4.2. AODV-RPL DIO RREP Option . . . . . . . . . . . . . . . . 8 4.2. AODV-RPL DIO RREP Option . . . . . . . . . . . . . . . . 9
4.3. AODV-RPL DIO Target Option . . . . . . . . . . . . . . . 10 4.3. AODV-RPL DIO Target Option . . . . . . . . . . . . . . . 10
5. Symmetric and Asymmetric Routes . . . . . . . . . . . . . . . 11 5. Symmetric and Asymmetric Routes . . . . . . . . . . . . . . . 11
6. AODV-RPL Operation . . . . . . . . . . . . . . . . . . . . . 13 6. AODV-RPL Operation . . . . . . . . . . . . . . . . . . . . . 13
6.1. Generating Route Request at OrigNode . . . . . . . . . . 13 6.1. Route Request Generation . . . . . . . . . . . . . . . . 13
6.2. Receiving and Forwarding Route Request . . . . . . . . . 14 6.2. Receiving and Forwarding RREQ messages . . . . . . . . . 14
6.3. Generating Route Reply at TargNode . . . . . . . . . . . 15 6.2.1. General Processing . . . . . . . . . . . . . . . . . 14
6.3.1. RREP-DIO for Symmetric route . . . . . . . . . . . . 15 6.2.2. Additional Processing for Multiple Targets . . . . . 15
6.3. Generating Route Reply (RREP) at TargNode . . . . . . . . 16
6.3.1. RREP-DIO for Symmetric route . . . . . . . . . . . . 16
6.3.2. RREP-DIO for Asymmetric Route . . . . . . . . . . . . 16 6.3.2. RREP-DIO for Asymmetric Route . . . . . . . . . . . . 16
6.3.3. RPLInstanceID Pairing . . . . . . . . . . . . . . . . 16 6.3.3. RPLInstanceID Pairing . . . . . . . . . . . . . . . . 16
6.4. Receiving and Forwarding Route Reply . . . . . . . . . . 17 6.4. Receiving and Forwarding Route Reply . . . . . . . . . . 17
7. Gratuitous RREP . . . . . . . . . . . . . . . . . . . . . . . 18 7. Gratuitous RREP . . . . . . . . . . . . . . . . . . . . . . . 18
8. Operation of Trickle Timer . . . . . . . . . . . . . . . . . 19 8. Operation of Trickle Timer . . . . . . . . . . . . . . . . . 19
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
9.1. New Mode of Operation: AODV-RPL . . . . . . . . . . . . . 19 9.1. New Mode of Operation: AODV-RPL . . . . . . . . . . . . . 19
9.2. AODV-RPL Options: RREQ, RREP, and Target . . . . . . . . 19 9.2. AODV-RPL Options: RREQ, RREP, and Target . . . . . . . . 19
10. Security Considerations . . . . . . . . . . . . . . . . . . . 20 10. Security Considerations . . . . . . . . . . . . . . . . . . . 20
11. Future Work . . . . . . . . . . . . . . . . . . . . . . . . . 20 11. Future Work . . . . . . . . . . . . . . . . . . . . . . . . . 20
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
12.1. Normative References . . . . . . . . . . . . . . . . . . 20 12.1. Normative References . . . . . . . . . . . . . . . . . . 20
12.2. Informative References . . . . . . . . . . . . . . . . . 21 12.2. Informative References . . . . . . . . . . . . . . . . . 21
Appendix A. ETX/RSSI Values to select S bit . . . . . . . . . . 21 Appendix A. Example: ETX/RSSI Values to select S bit . . . . . . 21
Appendix B. Changes to version 02 . . . . . . . . . . . . . . . 22 Appendix B. Changelog . . . . . . . . . . . . . . . . . . . . . 22
B.1. Changes to version 02 . . . . . . . . . . . . . . . . . . 22
B.2. Changes to version 03 . . . . . . . . . . . . . . . . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction 1. Introduction
RPL[RFC6550] is a IPv6 distance vector routing protocol for Low-power RPL[RFC6550] is a IPv6 distance vector routing protocol for Low-power
and Lossy Networks (LLNs), and is designed to support multiple and Lossy Networks (LLNs), and is designed to support multiple
traffic flows through a root-based Destination-Oriented Directed traffic flows through a root-based Destination-Oriented Directed
Acyclic Graph (DODAG). Typically, a router does not have routing Acyclic Graph (DODAG). Typically, a router does not have routing
information for most other routers. Consequently, for traffic information for most other routers. Consequently, for traffic
between routers within the DODAG (i.e., Point-to-Point (P2P) traffic) between routers within the DODAG (i.e., Point-to-Point (P2P) traffic)
data packets either have to traverse the root in non-storing mode, or data packets either have to traverse the root in non-storing mode, or
traverse a common ancestor in storing mode. Such P2P traffic is traverse a common ancestor in storing mode. Such P2P traffic is
thereby likely to traverse sub-optimal routes and may suffer severe thereby likely to traverse longer routes and may suffer severe
congestion near the DAG root [RFC6997], [RFC6998]. congestion near the DAG root [RFC6997], [RFC6998].
To discover optimal paths for P2P traffic flows in RPL, P2P-RPL To discover better paths for P2P traffic flows in RPL, P2P-RPL
[RFC6997] specifies a temporary DODAG where the source acts as a [RFC6997] specifies a temporary DODAG where the source acts as a
temporary root. The source initiates DIOs encapsulating the P2P temporary root. The source initiates DIOs encapsulating the P2P
Route Discovery option (P2P-RDO) with an address vector for both hop- Route Discovery option (P2P-RDO) with an address vector for both hop-
by-hop mode (H=1) and source routing mode (H=0). Subsequently, each by-hop mode (H=1) and source routing mode (H=0). Subsequently, each
intermediate router adds its IP address and multicasts the P2P mode intermediate router adds its IP address and multicasts the P2P mode
DIOs, until the message reaches the target node (TargNode). TargNode DIOs, until the message reaches the target node (TargNode), which
sends the "Discovery Reply" object. P2P-RPL is efficient for source then sends the "Discovery Reply" object. P2P-RPL is efficient for
routing, but much less efficient for hop-by-hop routing due to the source routing, but much less efficient for hop-by-hop routing due to
extra address vector overhead. However, for symmetric links, when the extra address vector overhead. However, for symmetric links,
the P2P mode DIO message is being multicast from the source hop-by- when the P2P mode DIO message is being multicast from the source hop-
hop, receiving nodes can infer a next hop towards the source. When by-hop, receiving nodes can infer a next hop towards the source.
TargNode subsequently replies to the source along the established When TargNode subsequently replies to the source along the
forward route, receiving nodes determine the next hop towards established forward route, receiving nodes determine the next hop
TargNode. In other words, it is efficient to use only routing tables towards TargNode. For hop-by-hop routes (H=1) over symmetric links,
for P2P-RDO message instead of "Address vector" for hop-by-hop routes this would allow efficient use of routing tables for P2P-RDO messages
(H=1) over symmetric links. instead of the "Address Vector".
RPL and P2P-RPL both specify the use of a single DODAG in networks of RPL and P2P-RPL both specify the use of a single DODAG in networks of
symmetric links, where the two directions of a link MUST both satisfy symmetric links, where the two directions of a link MUST both satisfy
the constraints of the objective function. This eliminates the the constraints of the objective function. This disallows the use of
possibility to use asymmetric links which are qualified in one asymmetric links which are qualified in one direction. But,
direction. But, application-specific routing requirements as defined application-specific routing requirements as defined in IETF ROLL
in IETF ROLL Working Group [RFC5548], [RFC5673], [RFC5826] and Working Group [RFC5548], [RFC5673], [RFC5826] and [RFC5867] may be
[RFC5867] may be satisfied by routing paths using bidirectional satisfied by routing paths using bidirectional asymmetric links. For
asymmetric links. For this purpose, [I-D.thubert-roll-asymlink] this purpose, [I-D.thubert-roll-asymlink] described bidirectional
describes bidirectional asymmetric links for RPL [RFC6550] with asymmetric links for RPL [RFC6550] with Paired DODAGs, for which the
Paired DODAGs, for which the DAG root (DODAGID) is common for two DAG root (DODAGID) is common for two Instances. This can satisfy
Instances. This can satisfy application-specific routing application-specific routing requirements for bidirectional
requirements for bidirectional asymmetric links in core RPL asymmetric links in core RPL [RFC6550]. Using P2P-RPL twice with
[RFC6550]. Using P2P-RPL twice with Paired DODAGs, on the other Paired DODAGs, on the other hand, requires two roots: one for the
hand, requires two roots: one for the source and another for the source and another for the target node due to temporary DODAG
target node due to temporary DODAG formation. For networks composed formation. For networks composed of bidirectional asymmetric links
of bidirectional asymmetric links (see Section 5), AODV-RPL specifies (see Section 5), AODV-RPL specifies P2P route discovery, utilizing
P2P route discovery, utilizing RPL with a new MoP. AODV-RPL makes RPL with a new MoP. AODV-RPL makes use of two multicast messages to
use of two multicast messages to discover possibly asymmetric routes, discover possibly asymmetric routes, which can achieve higher route
which can achieve higher route diversity. AODV-RPL eliminates the diversity. AODV-RPL eliminates the need for address vector overhead
need for address vector control overhead in hop-by-hop mode. This in hop-by-hop mode. This significantly reduces the control packet
significantly reduces the control packet size, which is important for size, which is important for Constrained LLN networks. Both
Constrained LLN networks. Both discovered routes (upward and discovered routes (upward and downward) meet the application specific
downward) meet the application specific metrics and constraints that metrics and constraints that are defined in the Objective Function
are defined in the Objective Function for each Instance [RFC6552]. for each Instance [RFC6552].
The route discovery process in AODV-RPL is modeled on the analogous The route discovery process in AODV-RPL is modeled on the analogous
procedure specified in AODV [RFC3561]. The on-demand nature of AODV procedure specified in AODV [RFC3561]. The on-demand nature of AODV
route discovery is natural for the needs of peer-to-peer routing in route discovery is natural for the needs of peer-to-peer routing in
RPL-based LLNs. AODV terminology has been adapted for use with AODV- RPL-based LLNs. AODV terminology has been adapted for use with AODV-
RPL messages, namely RREQ for Route Request, and RREP for Route RPL messages, namely RREQ for Route Request, and RREP for Route
Reply. AODV-RPL currently omits some features compared to AODV -- in Reply. AODV-RPL currently omits some features compared to AODV -- in
particular, flagging Route Errors, blacklisting unidirectional links, particular, flagging Route Errors, blacklisting unidirectional links,
multihoming, and handling unnumbered interfaces. multihoming, and handling unnumbered interfaces.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
[RFC2119]. Additionally, this document uses the following terms: [RFC2119]. This document uses the following terms:
AODV AODV
Ad Hoc On-demand Distance Vector Routing[RFC3561]. Ad Hoc On-demand Distance Vector Routing[RFC3561].
AODV-RPL Instance AODV-RPL Instance
Either the RREQ-Instance or RREP-Instance Either the RREQ-Instance or RREP-Instance
Asymmetric Route Asymmetric Route
The route from the OrigNode to the TargNode can traverse different The route from the OrigNode to the TargNode can traverse different
nodes than the route from the TargNode to the OrigNode. An nodes than the route from the TargNode to the OrigNode. An
asymmetric route may result from the asymmetry of links, such that asymmetric route may result from the asymmetry of links, such that
only one direction of the series of links fulfills the constraints only one direction of the series of links fulfills the constraints
in route discovery. If the OrigNode doesn't require an upward in route discovery.
route towards itself, the route is also considered as asymmetric.
Bi-directional Asymmetric Link Bi-directional Asymmetric Link
A link that can be used in both directions but with different link A link that can be used in both directions but with different link
characteristics. characteristics.
DIO
DODAG Information Object
DODAG RREQ-Instance (or simply RREQ-Instance) DODAG RREQ-Instance (or simply RREQ-Instance)
RPL Instance built using the DIO with RREQ option; used for RPL Instance built using the DIO with RREQ option; used for
control message transmission from OrigNode to TargNode, thus control message transmission from OrigNode to TargNode, thus
enabling data transmission from TargNode to OrigNode. enabling data transmission from TargNode to OrigNode.
DODAG RREP-Instance (or simply RREP-Instance) DODAG RREP-Instance (or simply RREP-Instance)
RPL Instance built using the DIO with RREP option; used for RPL Instance built using the DIO with RREP option; used for
control message transmission from TargNode to OrigNode thus control message transmission from TargNode to OrigNode thus
enabling data transmission from OrigNode to TargNode. enabling data transmission from OrigNode to TargNode.
Downward Direction Downward Direction
The direction from the OrigNode to the TargNode. The direction from the OrigNode to the TargNode.
Downward Route Downward Route
A route in the downward direction. A route in the downward direction.
hop-by-hop routing hop-by-hop routing
Routing when each node stores routing information about the next Routing when each node stores routing information about the next
hop. hop.
on-demand routing
Routing in which a route is established only when needed.
OrigNode OrigNode
The IPv6 router (Originating Node) initiating the AODV-RPL route The IPv6 router (Originating Node) initiating the AODV-RPL route
discovery to obtain a route to TargNode. discovery to obtain a route to TargNode.
Paired DODAGs Paired DODAGs
Two DODAGs for a single route discovery process of an application. Two DODAGs for a single route discovery process between OrigNode
and TargNode.
P2P P2P
Point-to-Point -- in other words, not constrained to traverse a Point-to-Point -- in other words, not constrained a priori to
common ancestor. traverse a common ancestor.
reactive routing
Same as "on-demand" routing.
RREQ-DIO message RREQ-DIO message
An AODV-RPL MoP DIO message containing the RREQ option. The An AODV-RPL MoP DIO message containing the RREQ option. The
RPLInstanceID in RREQ-DIO is assigned locally by the OrigNode. RPLInstanceID in RREQ-DIO is assigned locally by the OrigNode.
RREP-DIO message RREP-DIO message
An AODV-RPL MoP DIO message containing the RREP option. The An AODV-RPL MoP DIO message containing the RREP option. The
RPLInstanceID in RREP-DIO is typically paired to the one in the RPLInstanceID in RREP-DIO is typically paired to the one in the
associated RREQ-DIO message. associated RREQ-DIO message.
Source routing Source routing
The mechanism by which the source supplies the complete route A mechanism by which the source supplies the complete route
towards the target node along with each data packet [RFC6550]. towards the target node along with each data packet [RFC6550].
Symmetric route Symmetric route
The upstream and downstream routes traverse the same routers. The upstream and downstream routes traverse the same routers.
Both directions fulfill the constraints in route discovery.
TargNode TargNode
The IPv6 router (Target Node) for which OrigNode requires a route The IPv6 router (Target Node) for which OrigNode requires a route
and initiates Route Discovery within the LLN network. and initiates Route Discovery within the LLN network.
Upward Direction Upward Direction
The direction from the TargNode to the OrigNode. The direction from the TargNode to the OrigNode.
Upward Route Upward Route
A route in the upward direction. A route in the upward direction.
3. Overview of AODV-RPL 3. Overview of AODV-RPL
With AODV-RPL, routes from OrigNode to TargNode within the LLN With AODV-RPL, routes from OrigNode to TargNode within the LLN
network established are "on-demand". In other words, the route network established are "on-demand". In other words, the route
discovery mechanism in AODV-RPL is invoked reactively when OrigNode discovery mechanism in AODV-RPL is invoked reactively when OrigNode
has data for delivery to the TargNode but existing routes do not has data for delivery to the TargNode but existing routes do not
satisfy the application's requirements. The routes discovered by satisfy the application's requirements. The routes discovered by
AODV-RPL are point-to-point; in other words the routes are not AODV-RPL are not constrained to traverse a common ancestor. Unlike
constrained to traverse a common ancestor. Unlike core RPL [RFC6550] RPL [RFC6550] and P2P-RPL [RFC6997], AODV-RPL can enable asymmetric
and P2P-RPL [RFC6997], AODV-RPL can enable asymmetric communication communication paths in networks with bidirectional asymmetric links.
paths in networks with bidirectional asymmetric links. For this For this purpose, AODV-RPL enables discovery of two routes: namely,
purpose, AODV-RPL enables discovery of two routes: namely, one from one from OrigNode to TargNode, and another from TargNode to OrigNode.
OrigNode to TargNode, and another from TargNode to OrigNode. When When possible, AODV-RPL also enables symmetric route discovery along
possible, AODV-RPL also enables symmetric route discovery along
Paired DODAGs (see Section 5). Paired DODAGs (see Section 5).
In AODV-RPL, route discovery is initiated by forming a temporary DAG In AODV-RPL, routes are discovered by first forming a temporary DAG
rooted at the OrigNode. Paired DODAGs (Instances) are constructed rooted at the OrigNode. Paired DODAGs (Instances) are constructed
according to a new AODV-RPL Mode of Operation (MoP) during route according to the AODV-RPL Mode of Operation (MoP) during route
formation between the OrigNode and TargNode. The RREQ-Instance is formation between the OrigNode and TargNode. The RREQ-Instance is
formed by route control messages from OrigNode to TargNode whereas formed by route control messages from OrigNode to TargNode whereas
the RREP-Instance is formed by route control messages from TargNode the RREP-Instance is formed by route control messages from TargNode
to OrigNode (as shown in Figure 4). Intermediate routers join the to OrigNode. Intermediate routers join the Paired DODAGs based on
Paired DODAGs based on the rank as calculated from the DIO message. the rank as calculated from the DIO message. Henceforth in this
Henceforth in this document, the RREQ-DIO message means the AODV-RPL document, the RREQ-DIO message means the AODV-RPL mode DIO message
mode DIO message from OrigNode to TargNode, containing the RREQ from OrigNode to TargNode, containing the RREQ option (see
option. Similarly, the RREP-DIO message means the AODV-RPL mode DIO Section 4.1). Similarly, the RREP-DIO message means the AODV-RPL
message from TargNode to OrigNode, containing the RREP option. mode DIO message from TargNode to OrigNode, containing the RREP
Subsequently, the route discovered in the RREQ-Instance is used for option (see Section 4.2). The route discovered in the RREQ-Instance
data transmission from TargNode to OrigNode, and the route discovered is used for transmitting data from TargNode to OrigNode, and the
in RREP-Instance is used for Data transmission from OrigNode to route discovered in RREP-Instance is used for transmitting data from
TargNode. OrigNode to TargNode.
4. AODV-RPL DIO Options 4. AODV-RPL DIO Options
4.1. AODV-RPL DIO RREQ Option 4.1. AODV-RPL DIO RREQ Option
A RREQ-DIO message MUST carry exactly one RREQ option. OrigNode sets its IPv6 address in the DODAGID field of the RREQ-DIO
message. A RREQ-DIO message MUST carry exactly one RREQ option.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Option Length |S|H|X| Compr | L | MaxRank | | Type | Option Length |S|H|X| Compr | L | MaxRank |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Orig SeqNo | | | Orig SeqNo | |
+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+ |
| | | |
| | | |
| Address Vector (Optional, Variable Length) | | Address Vector (Optional, Variable Length) |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: DIO RREQ option format for AODV-RPL MoP Figure 1: DIO RREQ option format for AODV-RPL MoP
OrigNode supplies the following information in the RREQ option of the OrigNode supplies the following information in the RREQ option:
RREQ-Instance message:
Type Type
The type assigned to the RREQ option (see Section 9.2).
The type of the RREQ option(see Section 9.2).
Option Length Option Length
The length of the option in octets, excluding the Type and Length
Length of the option in octets excluding the Type and Length
fields. Variable due to the presence of the address vector and fields. Variable due to the presence of the address vector and
the number of octets elided according to the Compr value. the number of octets elided according to the Compr value.
S S
Symmetric bit indicating a symmetric route from the OrigNode to Symmetric bit indicating a symmetric route from the OrigNode to
the router issuing this RREQ-DIO. The bit SHOULD be set to 1 in the router transmitting this RREQ-DIO.
the RREQ-DIO when the OrigNode initiates the route discovery.
X
Reserved.
H H
Set to one for a hop-by-hop route. Set to zero for a source
route. This flag controls both the downstream route and upstream
route.
The OrigNode sets this flag to one if it desires a hop-by-hop X
route. It sets this flag to zero if it desires a source route. Reserved.
This flag is valid to both downstream route and upstream route.
Compr Compr
4-bit unsigned integer. Number of prefix octets that are elided 4-bit unsigned integer. Number of prefix octets that are elided
from the Address Vector. The octets elided are shared with the from the Address Vector. The octets elided are shared with the
IPv6 address in the DODAGID. IPv6 address in the DODAGID. This field is only used in source
routing mode (H=0). In hop-by-hop mode (H=1), this field MUST be
set to zero and ignored upon reception.
L L
2-bit unsigned integer. This field indicates the duration that a
node joining the temporary DAG in RREQ-Instance, including the
OrigNode and the TargNode. Once the time is reached, a node MUST
leave the DAG and stop sending or receiving any more DIOs for the
temporary DODAG. The detailed definition can be found in
[RFC6997].
* 0x00: No duration time imposed. 2-bit unsigned integer determining the duration that a node is
able to belong to the temporary DAG in RREQ-Instance, including
the OrigNode and the TargNode. Once the time is reached, a node
MUST leave the DAG and stop sending or receiving any more DIOs for
the temporary DODAG. The definition for the "L" bit is similar to
that found in [RFC6997], except that the values are adjusted to
enable arbitrarily long route lifetime.
* 0x00: No time limit imposed.
* 0x01: 2 seconds * 0x01: 2 seconds
* 0x02: 16 seconds * 0x02: 16 seconds
* 0x03: 64 seconds * 0x03: 64 seconds
It should be indicated here that L is not the route lifetime, L is independent from the route lifetime, which is defined in the
which is defined in the DODAG configuration option. The route DODAG configuration option. The route entries in hop-by-hop
entries in hop-by-hop routing and states of source routing can routing and states of source routing can still be maintained even
still be maintained even after the DAG expires. after the DAG expires.
MaxRank MaxRank
This field indicates the upper limit on the integer portion of the This field indicates the upper limit on the integer portion of the
rank. A node MUST NOT join a temporary DODAG if its own rank rank (calculated using the DAGRank() macro defined in [RFC6550]).
would equal to or higher than the limit. A value of 0 in this A value of 0 in this field indicates the limit is infinity.
field indicates the limit is infinity. For more details please
refer to [RFC6997].
OrigNode Sequence Number
Orig SeqNo
Sequence Number of OrigNode, defined similarly as in AODV Sequence Number of OrigNode, defined similarly as in AODV
[RFC3561]. [RFC3561].
Address Vector (Optional) Address Vector
A vector of IPv6 addresses representing the route that the RREQ- A vector of IPv6 addresses representing the route that the RREQ-
DIO has passed. It is only present when the 'H' bit is set to 0. DIO has passed. It is only present when the 'H' bit is set to 0.
The prefix of each address is elided according to the Compr field. The prefix of each address is elided according to the Compr field.
4.2. AODV-RPL DIO RREP Option A node MUST NOT join a RREQ instance if its own rank would equal to
or higher than MaxRank. Targnode can join the RREQ instance at a
rank whose integer portion is equal to the MaxRank. A router MUST
discard a received RREQ if the integer part of the advertised rank
equals or exceeds the MaxRank limit. This definition of MaxRank is
the same as that found in [RFC6997].
A RREP-DIO message MUST carry exactly one RREP option. 4.2. AODV-RPL DIO RREP Option
The TargNode supplies the following information in the RREP option: TargNode sets its IPv6 address in the DODAGID field of the RREP-DIO
message. A RREP-DIO message MUST carry exactly one RREP option.
TargNode supplies the following information in the RREP option:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Option Length |H|X| Compr | L | MaxRank | | Type | Option Length |G|H|X| Compr | L | MaxRank |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|T|G| SHIFT | Reserved | | | Shift |Rsv| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+ |
| | | |
| | | |
| Address Vector (Optional, Variable Length) | | Address Vector (Optional, Variable Length) |
. . . .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: DIO RREP option format for AODV-RPL MoP Figure 2: DIO RREP option format for AODV-RPL MoP
Type Type
The type of the RREP option (see Section 9.2) The type assigned to the RREP option (see Section 9.2)
Option Length Option Length
Length of the option in octets excluding the Type and Length The length of the option in octets, excluding the Type and Length
fields. Variable due to the presence of the address vector and fields. Variable due to the presence of the address vector and
the number of octets elided according to the Compr value. the number of octets elided according to the Compr value.
G
Gratuitous route (see Section 7).
H H
This bit indicates the downstream route is source routing (H=0) or Requests either source routing (H=0) or hop-by-hop (H=1) for the
hop-by-hop (H=1). It SHOULD be set to be the same as the 'H' bit downstream route. It MUST be set to be the same as the 'H' bit in
in RREQ option. RREQ option.
X X
Reserved. Reserved.
Compr Compr
4-bit unsigned integer. Same definition as in RREQ option. 4-bit unsigned integer. Same definition as in RREQ option.
L L
2-bit unsigned integer with the same definition as in Section 4.1. 2-bit unsigned integer defined as in RREQ option.
MaxRank MaxRank
Same definition as in RREQ option. Similarly to MaxRank in the RREQ message, this field indicates the
upper limit on the integer portion of the rank. A value of 0 in
T this field indicates the limit is infinity.
'T' is set to 1 to indicate that the RREP-DIO MUST include exactly
one AODV-RPL Target Option. Otherwise, the Target Option is not
necessary in the RREP-DIO.
G
Gratuitous route (see Section 7).
SHIFT Shift
6-bit unsigned integer. This field indicates the how many the 6-bit unsigned integer. This field is used to recover the
original InstanceID (see Section 6.3.3) is shifted (added an original InstanceID (see Section 6.3.3); 0 indicates that the
integer from 0 to 63). 0 indicates that the original InstanceID original InstanceID is used.
is used.
Reserved Rsv
Reserved for future usage; MUST be initialized to zero and MUST be MUST be initialized to zero and ignored upon reception.
ignored upon reception.
Address Vector (Optional) Address Vector
It is only present when the 'H' bit is set to 0. For an Only present when the 'H' bit is set to 0. For an asymmetric
asymmetric route, it is a vector of IPv6 addresses representing route, the Address Vector represents the IPv6 addresses of the
the route that the RREP-DIO has passed. For symmetric route, it route that the RREP-DIO has passed. For a symmetric route, it is
is the accumulated vector when the RREQ-DIO arrives at the the Address Vector when the RREQ-DIO arrives at the TargNode,
TargNode. unchanged during the transmission to the OrigNode.
4.3. AODV-RPL DIO Target Option 4.3. AODV-RPL DIO Target Option
The AODV-RPL Target Option is defined based on the Target Option in The AODV-RPL Target Option is defined based on the Target Option in
core RPL [RFC6550]: the Destination Sequence Number of the TargNode core RPL [RFC6550]: the Destination Sequence Number of the TargNode
is added. is added.
A RREQ-DIO message MUST carry at least one AODV-RPL Target Options. A RREQ-DIO message MUST carry at least one AODV-RPL Target Options.
A RREP-DIO message MUST carry exactly one AODV-RPL Target Option A RREP-DIO message MUST carry exactly one AODV-RPL Target Option.
encapsulating the address of the OrigNode if the 'T' bit is set to 1.
If an OrigNode want to discover routes to multiple TargNodes, and OrigNode can include multiple TargNode addresses via multiple AODV-
these routes share the same constraints, then the OrigNode can RPL Target Options in the RREQ-DIO, for routes that share the same
include all the addresses of the TargNodes into multiple AODV-RPL constraints. This reduces the cost to building only one DODAG.
Target Options in the RREQ-DIO, so that the cost can be reduced to Furthermore, a single Target Option can be used for different
building only one DODAG. Different addresses of the TargNodes can TargNode addresses if they share the same prefix; in that case the
merge if they share the same prefix. use of the destination sequence number is not defined in this
document.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Option Length | Dest SeqNo | Prefix Length | | Type | Option Length | Dest SeqNo | Prefix Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+ | + |
| Target Prefix (Variable Length) | | Target Prefix (Variable Length) |
. . . .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Target option format for AODV-RPL MoP Figure 3: Target option format for AODV-RPL MoP
Type Type
The type of the AODV-RPL Target Option (see Section 9.2) The type assigned to the AODV-RPL Target Option
Destination Sequence Number Dest SeqNo
In RREQ-DIO, if nonzero, it is the last known Sequence Number for In RREQ-DIO, if nonzero, it is the last known Sequence Number for
TargNode for which a route is desired. In RREP-DIO, it is the TargNode for which a route is desired. In RREP-DIO, it is the
destination sequence number associated to the route. destination sequence number associated to the route.
5. Symmetric and Asymmetric Routes 5. Symmetric and Asymmetric Routes
In Figure 4 and Figure 5, BR is the BorderRouter, O is the OrigNode, In Figure 4 and Figure 5, BR is the Border Router, O is the OrigNode,
R is an intermediate router, and T is the TargNode. If the RREQ-DIO R is an intermediate router, and T is the TargNode. If the RREQ-DIO
arrives over an interface that is known to be symmetric, and the 'S' arrives over an interface that is known to be symmetric, and the 'S'
bit is set to 1, then it remains as 1, as illustrated in Figure 4. bit is set to 1, then it remains as 1, as illustrated in Figure 4.
An intermediate router sends out RREQ-DIO with the 'S' bit set to 1, If an intermediate router sends out RREQ-DIO with the 'S' bit set to
meaning that all the one-hop links on the route from the OrigNode to 1, then all the one-hop links on the route from the OrigNode O to
this router meet the requirements of route discovery; thus the route this router meet the requirements of route discovery, and the route
can be used symmetrically. can be used symmetrically.
BR BR
/ | \ /----+----\
/ | \ / | \
/ | \ / | \
R R R R R R
/ \ | / \ _/ \ | / \
/ \ | / \ / \ | / \
/ \ | / \ / \ | / \
R -------- R --- R ----- R -------- R R -------- R --- R ----- R -------- R
/ \ <--S=1--> / \ <--S=1--> / \ / \ <--S=1--> / \ <--S=1--> / \
<--S=1--> \ / \ / <--S=1--> <--S=1--> \ / \ / <--S=1-->
/ \ / \ / \ / \ / \ / \
O ---------- R ------ R------ R ----- R ----------- T O ---------- R ------ R------ R ----- R ----------- T
/ \ / \ / \ / \ / \ / \ / \ / \
/ \ / \ / \ / \ / \ / \ / \ / \
/ \ / \ / \ / \ / \ / \ / \ / \
R ----- R ----------- R ----- R ----- R ----- R ---- R----- R R ----- R ----------- R ----- R ----- R ----- R ---- R----- R
>---- RREQ-Instance (Control: S-->D; Data: D-->S) -------> >---- RREQ-Instance (Control: O-->T; Data: T-->O) ------->
<---- RREP-Instance (Control: D-->S; Data: S-->D) -------< <---- RREP-Instance (Control: T-->O; Data: O-->T) -------<
Figure 4: AODV-RPL with Symmetric Paired Instances Figure 4: AODV-RPL with Symmetric Paired Instances
Upon receiving a RREQ-DIO with the 'S' bit set to 1, a node MUST Upon receiving a RREQ-DIO with the 'S' bit set to 1, a node
decide if this one-hop link can be used symmetrically, i.e., both the determines whether this one-hop link can be used symmetrically, i.e.,
two directions meet the requirements of data transmission. If the both the two directions meet the requirements of data transmission.
RREQ-DIO arrives over an interface that is not known to be symmetric, If the RREQ-DIO arrives over an interface that is not known to be
or is known to be asymmetric, the 'S' bit is set to 0. Moreover, if symmetric, or is known to be asymmetric, the 'S' bit is set to 0. If
the 'S' bit arrives already set to be '0', it is set to be '0' on the 'S' bit arrives already set to be '0', it is set to be '0' on
retransmission (Figure 5). Therefore, for asymmetric route, there is retransmission (Figure 5). Therefore, for asymmetric route, there is
at least one hop which doesn't fulfill the constraints in the two at least one hop which doesn't fulfill the constraints in the two
directions. Based on the 'S' bit received in RREQ-DIO, the TargNode directions. Based on the 'S' bit received in RREQ-DIO, the TargNode
decides whether or not the route is symmetric before transmitting the T determines whether or not the route is symmetric before
RREP-DIO message upstream towards the OrigNode. transmitting the RREP-DIO message upstream towards the OrigNode O.
The criterion and the corresponding metric used to determine if a The criteria used to determine whether or not each link is symmetric
one-hop link is symmetric or not is implementation specific and is beyond the scope of the document, and may be implementation-
beyond the scope of the document. Also, the difference in the metric specific. For instance, intermediate routers MAY use local
values for upward and downward directions of a link that can be information (e.g., bit rate, bandwidth, number of cells used in
establish its symmetric and asymmetric nature is implementation
specific. For instance, the intermediate routers MAY choose to use
local information (e.g., bit rate, bandwidth, number of cells used in
6tisch), a priori knowledge (e.g. link quality according to previous 6tisch), a priori knowledge (e.g. link quality according to previous
communication) or estimate the metric using averaging techniques or communication) or use averaging techniques as appropriate to the
any other means that is appropriate to the application context. application.
Appendix A describes an example method using the ETX and RSSI to Appendix A describes an example method using the ETX and RSSI to
estimate whether the link is symmetric in terms of link quality is estimate whether the link is symmetric in terms of link quality is
given in using an averaging technique. given in using an averaging technique.
BR BR
/ | \ /----+----\
/ | \ / | \
/ | \ / | \
R R R R R R
/ \ | / \ / \ | / \
/ \ | / \ / \ | / \
/ \ | / \ / \ | / \
R --------- R --- R ---- R --------- R R --------- R --- R ---- R --------- R
/ \ --S=1--> / \ --S=0--> / \ / \ --S=1--> / \ --S=0--> / \
--S=1--> \ / \ / --S=0--> --S=1--> \ / \ / --S=0-->
/ \ / \ / \ / \ / \ / \
O ---------- R ------ R------ R ----- R ----------- T O ---------- R ------ R------ R ----- R ----------- T
/ \ / \ / \ / \ / \ / \ / \ / \
/ <--S=0-- / \ / \ / <--S=0-- / <--S=0-- / \ / \ / <--S=0--
/ \ / \ / \ / \ / \ / \ / \ / \
R ----- R ----------- R ----- R ----- R ----- R ---- R----- R R ----- R ----------- R ----- R ----- R ----- R ---- R----- R
<--S=0-- <--S=0-- <--S=0-- <--S=0-- <--S=0-- <--S=0-- <--S=0-- <--S=0-- <--S=0-- <--S=0--
>---- RREQ-Instance (Control: S-->D; Data: D-->S) -------> >---- RREQ-Instance (Control: O-->T; Data: T-->O) ------->
<---- RREP-Instance (Control: D-->S; Data: S-->D) -------< <---- RREP-Instance (Control: T-->O; Data: O-->T) -------<
Figure 5: AODV-RPL with Asymmetric Paired Instances Figure 5: AODV-RPL with Asymmetric Paired Instances
6. AODV-RPL Operation 6. AODV-RPL Operation
6.1. Generating Route Request at OrigNode 6.1. Route Request Generation
The route discovery process is initiated on-demand when an The route discovery process is initiated when an application at the
application at the OrigNode has data to be transmitted to the OrigNode has data to be transmitted to the TargNode, but does not
TargNode, but no route for the target exists or the current routes have a route for the target that fulfills the requirements of the
don't fulfill the requirements of the data transmission. In this data transmission. In this case, the OrigNode builds a local
case, the OrigNode MUST build a local RPLInstance and a DODAG rooted RPLInstance and a DODAG rooted at itself. Then it transmits a DIO
at itself. Then it begins to send out DIO message in AODV-RPL MoP message containing exactly one RREQ option (see Section 4.1) via
via link-local multicast. The DIO MUST contain exactly one RREQ link-local multicast. The DIO MUST contain at least one AODV-RPL
option as defined in Section 4.1, and at least one AODV-RPL Target Target Option (see Section 4.3). The 'S' bit in RREQ-DIO sent out by
Option as defined in Figure 3. This DIO message is noted as RREQ- the OrigNode is set to 1.
DIO. The 'S' bit in RREQ-DIO sent out by the OrigNode is set as 1.
The maintenance of Originator and Destination Sequence Number in the The OrigNode maintains its Sequence Number as defined in AODV
RREQ option is as defined in AODV [RFC3561]. [RFC3561]. Namely, the OrigNode increments its Sequence number each
time it initiate a new route discovery operation by transmitting a
new RREQ message. Similarly, TargNode increments its Sequence number
each time it transmits a RREP message in response to a new RREQ
message (one with an incremented Sequence Number for OrigNode).
The address in the AODV-RPL Target Option can be a unicast IPv6 The address in the AODV-RPL Target Option can be a unicast IPv6
address, a prefix or a multicast address. The OrigNode can initiate address, or a prefix. The OrigNode can initiate the route discovery
the route discovery process for multiple targets simultaneously by process for multiple targets simultaneously by including multiple
including multiple AODV-RPL Target Options, and within a RREQ-DIO the AODV-RPL Target Options, and within a RREQ-DIO the requirements for
requirements for the routes to different TargNodes MUST be the same. the routes to different TargNodes MUST be the same.
The OrigNode can maintain different RPLInstances to discover routes OrigNode can maintain different RPLInstances to discover routes with
with different requirements to the same targets. Due to the different requirements to the same targets. Using the InstanceID
InstanceID pairing mechanism Section 6.3.3, route replies (RREP-DIOs) pairing mechanism (see Section 6.3.3), route replies (RREP-DIOs) for
from different paired RPLInstances can be distinguished. different RPLInstances can be distinguished.
The transmission of RREQ-DIO follows the Trickle timer. When the L The transmission of RREQ-DIO obeys the Trickle timer. If the
duration has transpired, the OrigNode MUST leave the DODAG and stop duration specified by the "L" bit has elapsed, the OrigNode MUST
sending any RREQ-DIOs in the related RPLInstance. leave the DODAG and stop sending RREQ-DIOs in the related
RPLInstance.
6.2. Receiving and Forwarding Route Request 6.2. Receiving and Forwarding RREQ messages
Upon receiving a RREQ-DIO, a router out of the RREQ-instance goes 6.2.1. General Processing
through the following steps:
Upon receiving a RREQ-DIO, a router which does not belong to the
RREQ-instance goes through the following steps:
Step 1: Step 1:
If the 'S' bit in the received RREQ-DIO is set to 1, the router If the 'S' bit in the received RREQ-DIO is set to 1, the router
MUST look into the two directions of the link by which the RREQ- MUST check the two directions of the link by which the RREQ-DIO is
DIO is received. In case that the downward (i.e. towards the received. In case that the downward (i.e. towards the TargNode)
TargNode) direction of the link can't fulfill the requirements, direction of the link can't fulfill the requirements, the link
then the link can't be used symmetrically, thus the 'S' bit of the can't be used symmetrically, thus the 'S' bit of the RREQ-DIO to
RREQ-DIO to be send out MUST be set as 0. If the 'S' bit in the be sent out MUST be set as 0. If the 'S' bit in the received
received RREQ-DIO is set to 0, the router MUST look only into the RREQ-DIO is set to 0, the router only checks into the upward
upward direction (i.e. towards the OrigNode) of the link. If the direction (towards the OrigNode) of the link.
upward direction of the link can fulfill the requirements
indicated in the constraint option, and the router's rank would be
inferior to the MaxRank limit, the router chooses to join in the
DODAG of the RREQ-Instance. The router issuing the received RREQ-
DIO is selected as the preferred parent. Afterwards, other RREQ-
DIO message can be received. How to maintain the parent set,
select the preferred parent, and update the router's rank follows
the core RPL and the OFs defined in ROLL WG.
In case that the constraint or the MaxRank limit is not fulfilled,
the router MUST NOT join in the DODAG. Otherwise, go to the
following steps 2, 3, 4 and 5.
A router MUST discard a received RREQ-DIO if the advertised rank If the upward direction of the link can fulfill the requirements
equals or exceeds the MaxRank limit. indicated in the constraint option, and the router's rank would
not exceed the MaxRank limit, the router joins the DODAG of the
RREQ-Instance. The router that transmitted the received RREQ-DIO
is selected as the preferred parent. Later, other RREQ-DIO
messages might be received. How to maintain the parent set,
select the preferred parent, and update the router's rank obeys
the core RPL and the OFs defined in ROLL WG. In case that the
constraint or the MaxRank limit is not fulfilled, the router MUST
discard the received RREQ-DIO and MUST NOT join the DODAG.
Step 2: Step 2:
Then the router checks if one of its addresses is included in one Then the router checks if one of its addresses is included in one
of the AODV-RPL Target Options or belongs to the indicated of the AODV-RPL Target Options. If so, this router is one of the
multicast group. If so, this router is one of the TargNodes. TargNodes. Otherwise, it is an intermediate router.
Otherwise, it is an intermediate router.
Step 3: Step 3:
If the 'H' bit is set to 1, then the router (TargNode or If the 'H' bit is set to 1, then the router (TargNode or
intermediate) MUST build route entry towards its preferred parent. intermediate) MUST build the upward route entry accordingly. The
The route entry SHOULD be stored along with the associated route entry MUST include at least the following items: Source
RPLInstanceID and DODAGID. If the 'H' bit is set to 0, an Address, InstanceID, Destination Address, Next Hop and Lifetime.
intermediate router MUST include the address of the interface The Destination Address and the InstanceID can be respectively
receiving the RREQ-DIO into the address vector. learned from the DODAGID and the RPLInstanceID of the RREQ-DIO,
and the Source Address is copied from the AODV-RPL Target Option.
The next hop is the preferred parent. And the lifetime is set
according to DODAG configuration and can be extended when the
route is actually used.
If the 'H' bit is set to 0, an intermediate router MUST include
the address of the interface receiving the RREQ-DIO into the
address vector.
Step 4: Step 4:
If there are multiple AODV-RPL Target Options in the received An intermediate router transmits a RREQ-DIO via link-local
RREQ-DIO, a TargNode SHOULD continue sending RREQ-DIO to reach multicast. TargNode prepares a RREP-DIO.
other targets. When preparing its own RREQ-DIO, the TargNode MUST
delete the AODV-RPL Target Option related to its own address, so
that the routers which higher ranks would know the route to this
target has already been found. When an intermediate router
receives several RREQ-DIOs which include different lists of AODV-
RPL Target Options, the intersection of these lists will be
included in its own RREQ-DIO. If the intersection is empty, the
router SHOULD NOT send out any RREQ-DIO. Any RREQ-DIO message
with different AODV-RPL Target Options coming from a router with
higher rank is ignored.
Step 5: 6.2.2. Additional Processing for Multiple Targets
For an intermediate router, it sends out its own RREQ-DIO via If the OrigNode tries to reach multiple TargNodes in a single RREQ-
link-local multicast. For a TargNode, it can begin to prepare the instance, one of the TargNodes can be an intermediate router to the
RREP-DIO. others, therefore it SHOULD continue sending RREQ-DIO to reach other
targets. In this case, before rebroadcasting the RREQ-DIO, a
TargNode MUST delete the Target Option encapsulating its own address,
so that downstream routers with higher ranks do not try to create a
route to this TargetNode.
6.3. Generating Route Reply at TargNode An intermediate router could receive several RREQ-DIOs from routers
with lower ranks in the same RREQ-instance but have different lists
of Target Options. When rebroadcasting the RREQ-DIO, the
intersection of these lists SHOULD be included. For example, suppose
two RREQ-DIOs are received with the same RPLInstance and OrigNode.
Suppose further that the first RREQ has (T1, T2) as the targets, and
the second one has (T2, T4) as targets. Then only T2 needs to be
included in the generated RREQ-DIO. If the intersection is empty, it
means that all the targets have been reached, and the router SHOULD
NOT send out any RREQ-DIO. Any RREQ-DIO message with different AODV-
RPL Target Options coming from a router with higher rank is ignored.
6.3. Generating Route Reply (RREP) at TargNode
6.3.1. RREP-DIO for Symmetric route 6.3.1. RREP-DIO for Symmetric route
When a RREQ-DIO arrives at a TargNode with the 'S' bit set to 1, it If a RREQ-DIO arrives at TargNode with the 'S' bit set to 1, there is
means there exists a symmetric route in which the two directions can a symmetric route along which both directions can fulfill the
fulfill the requirements. Other RREQ-DIOs can bring the upward requirements. Other RREQ-DIOs might later provide asymmetric upward
direction of asymmetric routes (i.e. S=0). How to choose between a routes (i.e. S=0). Selection between a qualified symmetric route
qualified symmetric route and an asymmetric route hopefully having and an asymmetric route that might have better performance is
better performance is implementation-specific and out of scope. If implementation-specific and out of scope. If the implementation uses
the implementation choose to use the symmetric route, the TargNode the symmetric route, the TargNode MAY delay transmitting the RREP-DIO
MAY send out the RREP-DIO after a duration RREP_WAIT_TIME to wait for for duration RREP_WAIT_TIME to await a better symmetric route.
the convergence of RD to an optimal symmetric route.
For symmetric route, the RREP-DIO message is sent via unicast to the For a symmetric route, the RREP-DIO message is unicast to the next
OrigNode; therefore the DODAG in RREP-Instance doesn't need to be hop according to the accumulated address vector (H=0) or the route
actually built. The RPLInstanceID in the RREP-Instance is paired as entry (H=1). Thus the DODAG in RREP-Instance does not need to be
defined in Section 6.3.3. The 'S' bit in the base DIO remains as 1. built. The RPLInstanceID in the RREP-Instance is paired as defined
In the RREP option, The 'SHIFT' field and the 'T' bit are set as in Section 6.3.3. In case the 'H' bit is set to 0, the address
defined in Section 6.3.3. The address vector received in the RREQ- vector received in the RREQ-DIO MUST be included in the RREP-DIO.
DIO MUST be included in this RREP option in case the 'H' bit is set The address of the OrigNode MUST be encapsulated in an AODV-RPL
to 0 (both in RREQ-DIO and RREP-DIO). If the 'T' bit is set to 1, Target Option and included in this RREP-DIO message, and the Dest
the address of the OrigNode MUST be encapsulated in an AODV-RPL SeqNo is incremented, as is done in AODV [RFC3561].
Target Option and included in this RREP-DIO message, and the
Destination Sequence Number is set according to AODV [RFC3561].
6.3.2. RREP-DIO for Asymmetric Route 6.3.2. RREP-DIO for Asymmetric Route
When a RREQ-DIO arrives at a TargNode with the 'S' bit set to 0, the When a RREQ-DIO arrives at a TargNode with the 'S' bit set to 0, the
TargNode MUST build a DODAG in the RREP-Instance rooted at itself in TargNode MUST build a DODAG in the RREP-Instance rooted at itself in
order to discover the downstream route from the OrigNode to the order to discover the downstream route from the OrigNode to the
TargNode. The RREP-DIO message MUST be send out via link-local TargNode. The RREP-DIO message MUST be re-transmitted via link-local
multicast until the OrigNode is reached or the MaxRank limit is multicast until the OrigNode is reached or MaxRank is exceeded.
exceeded.
The settings of the RREP-DIO are the same as in symmetric route. The settings of the fields in RREP option are the same as in
symmetric route except for the 'S' bit.
6.3.3. RPLInstanceID Pairing 6.3.3. RPLInstanceID Pairing
Since the RPLInstanceID is assigned locally (i.e., there is no Since the RPLInstanceID is assigned locally (i.e., there is no
coordination between routers in the assignment of RPLInstanceID) the coordination between routers in the assignment of RPLInstanceID), the
tuple (RPLInstanceID, DODAGID, Address in the AODV-RPL Target Option) tuple (OrigNode, TargNode, RPLInstanceID) is needed to uniquely
is needed to uniquely identify a DODAG in an AODV-RPL instance. identify a discovered route. The upper layer applications may have
Between the OrigNode and the TargNode, there can be multiple AODV-RPL different requirements and they can initiate the route discoveries
instances when applications upper layer have different requirements. simultaneously. Thus between the same pair of OrigNode and TargNode,
Therefore the RREQ-Instance and the RREP-Instance in the same route there can be multiple AODV-RPL instances. To avoid any mismatch, the
discovery MUST be paired. The way to realize this is to pair their RREQ-Instance and the RREP-Instance in the same route discovery MUST
RPLInstance IDs. be paired somehow, e.g. using the RPLInstanceID.
Typically, the two InstanceIDs are set as the local InstanceID in
core RPL:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|1|D| ID | Local RPLInstanceID in 0..63
+-+-+-+-+-+-+-+-+
Figure 6: Local Instance ID
The first bit is set to 1 indicating the RPLInstanceID is local. The
'D' bit here is used to distinguish the two AODV-RPL instances: D=0
for RREQ-Instance, D=1 for RREP-Instance. The ID of 6 bits SHOULD be
the same for RREQ-Instance and RREP-Instance. Here, the 'D' bit is
used slightly differently than in RPL.
When preparing the RREP-DIO, a TargNode could find the RPLInstanceID When preparing the RREP-DIO, a TargNode could find the RPLInstanceID
to be used for the RREP-Instance is already occupied by another to be used for the RREP-Instance is already occupied by another RPL
instance from an earlier route discovery operation which is still Instance from an earlier route discovery operation which is still
active. In other words, two OrigNodes need routes to the same active. In other words, it might happen that two distinct OrigNodes
TargNode and they happen to use the same RPLInstanceID for RREQ- need routes to the same TargNode, and they happen to use the same
Instance. In this case, the occupied RPLInstanceID MUST NOT be used RPLInstanceID for RREQ-Instance. In this case, the occupied
again. Then this RPLInstanceID SHOULD be shifted into another RPLInstanceID MUST NOT be used again. Then the second RPLInstanceID
integer and shifted back to the original one at the OrigNode. In MUST be shifted into another integer so that the two RREP-instances
RREP option, the SHIFT field indicates the how many the original can be distinguished. In RREP option, the Shift field indicates the
RPLInstanceID is shifted. When the new InstanceID after shifting shift to be applied to original RPLInstanceID. When the new
exceeds 63, it will come back counting from 0. For example, the InstanceID after shifting exceeds 63, it rolls over starting at 0.
original InstanceID is 60, and shifted by 6, the new InstanceID will For example, the original InstanceID is 60, and shifted by 6, the new
be 2. The 'T' MUST be set to 1 to make sure the two RREP-DIOs can be InstanceID will be 2. Related operations can be found in
distinguished by the address of the OrigNode in the AODV-RPL Target Section 6.4.
Option.
6.4. Receiving and Forwarding Route Reply 6.4. Receiving and Forwarding Route Reply
Upon receiving a RREP-DIO, a router out of the RREP-Instance goes Upon receiving a RREP-DIO, a router which does not belong to the
through the following steps: RREQ-instance goes through the following steps:
Step 1: Step 1:
If the 'S' bit of the RREP-DIO is set to 0, the router MUST look If the 'S' bit is set to 1, the router proceeds to step 2.
into the downward direction of the link (towards the TargNode) by
If the 'S' bit of the RREP-DIO is set to 0, the router MUST check
the downward direction of the link (towards the TargNode) over
which the RREP-DIO is received. If the downward direction of the which the RREP-DIO is received. If the downward direction of the
link can fulfill the requirements indicated in the constraint link can fulfill the requirements indicated in the constraint
option, and the router's rank would be inferior to the MaxRank option, and the router's rank would not exceed the MaxRank limit,
limit, the router chooses to join in the DODAG of the RREP- the router joins the DODAG of the RREP-Instance. The router that
Instance. The router issuing the received RREP-DIO is selected as transmitted the received RREP-DIO is selected as the preferred
the preferred parent. Afterwards, other RREQ-DIO messages can be parent. Afterwards, other RREP-DIO messages can be received. How
received. How to maintain the parent set, select the preferred to maintain the parent set, select the preferred parent, and
parent, and update the router's rank follows the core RPL and the update the router's rank obeys the core RPL and the OFs defined in
OFs defined in ROLL WG. ROLL WG.
If the constraints are not fulfilled, the router MUST NOT join in
the DODAG, and will not go through steps 2, 3, and 4.
A router MUST discard a received RREQ-DIO if the advertised rank
equals or exceeds the MaxRank limit.
If the 'S' bit is set to 1, the router does nothing in this step. If the constraints are not fulfilled, the router MUST NOT join the
DODAG; the router MUST discard the RREQ-DIO, and does not execute
the remaining steps in this section.
Step 2: Step 2:
Then the router checks if one of its addresses is included in the The router next checks if one of its addresses is included in the
AODV-RPL Target Option. If so, this router is the OrigNode of the AODV-RPL Target Option. If so, this router is the OrigNode of the
route discovery. Otherwise, it is an intermediate router. route discovery. Otherwise, it is an intermediate router.
Step 3: Step 3:
If the 'H' bit is set to 1, then the router (OrigNode or If the 'H' bit is set to 1, then the router (OrigNode or
intermediate) MUST build route entry including the RPLInstanceID intermediate) MUST build a downward route entry. The route entry
of RREP-Instance and the DODAGID. For symmetric route, the route SHOULD include at least the following items: OrigNode Address,
entry is to the router from which the RREP-DIO is received. For InstanceID, TargNode Address as destination, Next Hop and
asymmetric route, the route entry is to the preferred parent in Lifetime. For a symmetric route, the next hop in the route entry
the DODAG of RREQ-Instance. is the router from which the RREP-DIO is received. For an
asymmetric route, the next hop is the preferred parent in the
DODAG of RREQ-Instance. The InstanceID in the route entry MUST be
the original RPLInstanceID (after subtracting the Shift field
value). The source address is learned from the AODV-RPL Target
Option, and the destination address is learned from the DODAGID.
The lifetime is set according to DODAG configuration and can be
extended when the route is actually used.
If the 'H' bit is set to 0, for asymmetric route, an intermediate If the 'H' bit is set to 0, for an asymmetric route, an
router MUST include the address of the interface receiving the intermediate router MUST include the address of the interface
RREP-DIO into the address vector, and for symmetric route, there receiving the RREP-DIO into the address vector; for a symmetric
is nothing to do in this step. route, there is nothing to do in this step.
Step 4: Step 4:
For an intermediate router, in case of asymmetric route, the RREP- If the receiver is the OrigNode, it can start transmitting the
DIO is sent out via link-local multicast; in case of symmetric application data to TargNode along the path as provided in RREP-
route, the RREP-DIO is unicasted to the OrigNode via the next hop Instance, and processing for the RREP-DIO is complete. Otherwise,
in source routing (H=0), or via the next hop in the route entry in case of an asymmetric route, the intermediate router transmits
built in the RREQ-Instance (H=1). For the OrigNode, it can start the RREP-DIO via link-local multicast. In case of a symmetric
transmitting the application data to TargNode along the path as route, the RREP-DIO message is unicast to the next hop according
discovered through RREP-Instance. to the address vector in the RREP-DIO (H=0) or the local route
entry (H=1). The RPLInstanceID in the transmitted RREP-DIO is the
same as the value in the received RREP-DIO.
7. Gratuitous RREP 7. Gratuitous RREP
In some cases, an Intermediate router that receives a RREQ-DIO In some cases, an Intermediate router that receives a RREQ-DIO
message MAY transmit a "Gratuitous" RREP-DIO message back to OrigNode message MAY transmit a "Gratuitous" RREP-DIO message back to OrigNode
instead of continuing to multicast the RREQ-DIO towards TargNode. instead of continuing to multicast the RREQ-DIO towards TargNode.
The intermediate router effectively builds the RREP-Instance on The intermediate router effectively builds the RREP-Instance on
behalf of the actual TargNode. The 'G' bit of the RREP option is behalf of the actual TargNode. The 'G' bit of the RREP option is
provided to distinguish the Gratuitous RREP-DIO (G=1) sent by the provided to distinguish the Gratuitous RREP-DIO (G=1) sent by the
Intermediate node from the RREP-DIO sent by TargNode (G=0). Intermediate node from the RREP-DIO sent by TargNode (G=0).
The gratuitous RREP-DIO can be sent out when an intermediate router R The gratuitous RREP-DIO can be sent out when an intermediate router R
receives a RREQ-DIO for a TargNode T, and R happens to have both receives a RREQ-DIO for a TargNode T, and R happens to have both
forward and reverse routes to T which also fulfill the requirements. downward and upward routes to T which also fulfill the requirements.
In case of source routing, the intermediate router R MUST unicast the In case of source routing, the intermediate router R MUST unicast the
received RREQ-DIO to TargNode T including the address vector between received RREQ-DIO to TargNode T including the address vector between
the OrigNode O and the router R. Thus T can have a complete address the OrigNode O and the router R. Thus T can have a complete upward
vector between O and itself. Then T MUST unicast a RREP-DIO route address vector from itself to O. Then R MUST send out the
including the address vector between T and R. gratuitous RREP-DIO including the address vector from R to T.
In case of hop-by-hop routing, R MUST unicast the received RREQ-DIO In case of hop-by-hop routing, R MUST unicast the received RREQ-DIO
to T. The routers along the route SHOULD build new route entries to T. The routers along the route SHOULD build new route entries
with the related RPLInstanceID and DODAGID in the downward direction. with the related RPLInstanceID and DODAGID in the downward direction.
Then T MUST unicast the RREP-DIO to R, and the routers along the Then T MUST unicast the RREP-DIO to R, and the routers along the
route SHOULD build new route entries in the upward direction. Upon route SHOULD build new route entries in the upward direction. Upon
received the unicast RREP-DIO, R sends the gratuitous RREP-DIO to the received the unicast RREP-DIO, R sends the gratuitous RREP-DIO to the
OrigNode as the same way defined in Section 6.3. OrigNode as the same way defined in Section 6.3.
8. Operation of Trickle Timer 8. Operation of Trickle Timer
skipping to change at page 19, line 27 skipping to change at page 19, line 27
9. IANA Considerations 9. IANA Considerations
9.1. New Mode of Operation: AODV-RPL 9.1. New Mode of Operation: AODV-RPL
IANA is required to assign a new Mode of Operation, named "AODV-RPL" IANA is required to assign a new Mode of Operation, named "AODV-RPL"
for Point-to-Point(P2P) hop-by-hop routing under the RPL registry. for Point-to-Point(P2P) hop-by-hop routing under the RPL registry.
The value of TBD1 is assigned from the "Mode of Operation" space The value of TBD1 is assigned from the "Mode of Operation" space
[RFC6550]. [RFC6550].
+-------------+---------------+---------------+ +-------------+---------------+---------------+
| Value | Description | Reference | | Value | Description | Reference |
+-------------+---------------+---------------+ +-------------+---------------+---------------+
| TBD1 (5) | AODV-RPL | This document | | TBD1 (5) | AODV-RPL | This document |
+-------------+---------------+---------------+ +-------------+---------------+---------------+
Figure 7: Mode of Operation Figure 6: Mode of Operation
9.2. AODV-RPL Options: RREQ, RREP, and Target 9.2. AODV-RPL Options: RREQ, RREP, and Target
Three entries are required for new AODV-RPL options "RREQ", "RREP" Three entries are required for new AODV-RPL options "RREQ", "RREP"
and "AODV-RPL Target" with values of TBD2 (0x0A), TBD3 (0x0B) and and "AODV-RPL Target" with values of TBD2 (0x0A), TBD3 (0x0B) and
TBD4 (0x0C) from the "RPL Control Message Options" space [RFC6550]. TBD4 (0x0C) from the "RPL Control Message Options" space [RFC6550].
+-------------+------------------------+---------------+ +-------------+------------------------+---------------+
| Value | Meaning | Reference | | Value | Meaning | Reference |
+-------------+------------------------+---------------+ +-------------+------------------------+---------------+
| TBD2 (0x0A) | RREQ Option | This document | | TBD2 (0x0A) | RREQ Option | This document |
+-------------+------------------------+---------------+ +-------------+------------------------+---------------+
| TBD3 (0x0B) | RREP Option | This document | | TBD3 (0x0B) | RREP Option | This document |
+-------------+------------------------+---------------+ +-------------+------------------------+---------------+
| TBD3 (0x0C) | AODV-RPL Target Option | This document | | TBD3 (0x0C) | AODV-RPL Target Option | This document |
+-------------+------------------------+---------------+ +-------------+------------------------+---------------+
Figure 8: AODV-RPL Options Figure 7: AODV-RPL Options
10. Security Considerations 10. Security Considerations
This document does not introduce additional security issues compared This document does not introduce additional security issues compared
to base RPL. For general RPL security considerations, see [RFC6550]. to base RPL. For general RPL security considerations, see [RFC6550].
11. Future Work 11. Future Work
There has been some discussion about how to determine the initial There has been some discussion about how to determine the initial
state of a link after an AODV-RPL-based network has begun operation. state of a link after an AODV-RPL-based network has begun operation.
skipping to change at page 21, line 27 skipping to change at page 21, line 27
JP., and R. Alexander, "RPL: IPv6 Routing Protocol for JP., and R. Alexander, "RPL: IPv6 Routing Protocol for
Low-Power and Lossy Networks", RFC 6550, Low-Power and Lossy Networks", RFC 6550,
DOI 10.17487/RFC6550, March 2012, DOI 10.17487/RFC6550, March 2012,
<https://www.rfc-editor.org/info/rfc6550>. <https://www.rfc-editor.org/info/rfc6550>.
[RFC6552] Thubert, P., Ed., "Objective Function Zero for the Routing [RFC6552] Thubert, P., Ed., "Objective Function Zero for the Routing
Protocol for Low-Power and Lossy Networks (RPL)", Protocol for Low-Power and Lossy Networks (RPL)",
RFC 6552, DOI 10.17487/RFC6552, March 2012, RFC 6552, DOI 10.17487/RFC6552, March 2012,
<https://www.rfc-editor.org/info/rfc6552>. <https://www.rfc-editor.org/info/rfc6552>.
[RFC6997] Goyal, M., Ed., Baccelli, E., Philipp, M., Brandt, A., and
J. Martocci, "Reactive Discovery of Point-to-Point Routes
in Low-Power and Lossy Networks", RFC 6997,
DOI 10.17487/RFC6997, August 2013,
<https://www.rfc-editor.org/info/rfc6997>.
[RFC6998] Goyal, M., Ed., Baccelli, E., Brandt, A., and J. Martocci, [RFC6998] Goyal, M., Ed., Baccelli, E., Brandt, A., and J. Martocci,
"A Mechanism to Measure the Routing Metrics along a Point- "A Mechanism to Measure the Routing Metrics along a Point-
to-Point Route in a Low-Power and Lossy Network", to-Point Route in a Low-Power and Lossy Network",
RFC 6998, DOI 10.17487/RFC6998, August 2013, RFC 6998, DOI 10.17487/RFC6998, August 2013,
<https://www.rfc-editor.org/info/rfc6998>. <https://www.rfc-editor.org/info/rfc6998>.
12.2. Informative References 12.2. Informative References
[I-D.thubert-roll-asymlink] [I-D.thubert-roll-asymlink]
Thubert, P., "RPL adaptation for asymmetrical links", Thubert, P., "RPL adaptation for asymmetrical links",
draft-thubert-roll-asymlink-02 (work in progress), draft-thubert-roll-asymlink-02 (work in progress),
December 2011. December 2011.
Appendix A. ETX/RSSI Values to select S bit [RFC6997] Goyal, M., Ed., Baccelli, E., Philipp, M., Brandt, A., and
J. Martocci, "Reactive Discovery of Point-to-Point Routes
in Low-Power and Lossy Networks", RFC 6997,
DOI 10.17487/RFC6997, August 2013,
<https://www.rfc-editor.org/info/rfc6997>.
Appendix A. Example: ETX/RSSI Values to select S bit
We have tested the combination of "RSSI(downstream)" and "ETX We have tested the combination of "RSSI(downstream)" and "ETX
(upstream)" to decide whether the link is symmetric or asymmetric at (upstream)" to determine whether the link is symmetric or asymmetric
the intermediate nodes. The example of how the ETX and RSSI values at the intermediate nodes. The example of how the ETX and RSSI
are used in conjuction is explained below: values are used in conjuction is explained below:
Source---------->NodeA---------->NodeB------->Destination Source---------->NodeA---------->NodeB------->Destination
Figure 9: Communication link from Source to Destination Figure 8: Communication link from Source to Destination
+-------------------------+----------------------------------------+ +-------------------------+----------------------------------------+
| RSSI at NodeA for NodeB | Expected ETX at NodeA for NodeB->NodeA | | RSSI at NodeA for NodeB | Expected ETX at NodeA for NodeB->NodeA |
+-------------------------+----------------------------------------+ +-------------------------+----------------------------------------+
| > -15 | 150 | | > -15 | 150 |
| -25 to -15 | 192 | | -25 to -15 | 192 |
| -35 to -25 | 226 | | -35 to -25 | 226 |
| -45 to -35 | 662 | | -45 to -35 | 662 |
| -55 to -45 | 993 | | -55 to -45 | 993 |
+-------------------------+----------------------------------------+ +-------------------------+----------------------------------------+
skipping to change at page 22, line 39 skipping to change at page 22, line 39
way of knowing the value of ETX from NodeB->NodeA. Using physical way of knowing the value of ETX from NodeB->NodeA. Using physical
testbed experiments and realistic wireless channel propagation testbed experiments and realistic wireless channel propagation
models, one can determine a relationship between RSSI and ETX models, one can determine a relationship between RSSI and ETX
representable as an expression or a mapping table. Such a representable as an expression or a mapping table. Such a
relationship in turn can be used to estimate ETX value at nodeA for relationship in turn can be used to estimate ETX value at nodeA for
link NodeB--->NodeA from the received RSSI from NodeB. Whenever link NodeB--->NodeA from the received RSSI from NodeB. Whenever
nodeA determines that the link towards the nodeB is bi-directional nodeA determines that the link towards the nodeB is bi-directional
asymmetric then the "S" bit is set to "S=0". Later on, the link from asymmetric then the "S" bit is set to "S=0". Later on, the link from
NodeA to Destination is asymmetric with "S" bit remains to "0". NodeA to Destination is asymmetric with "S" bit remains to "0".
Appendix B. Changes to version 02 Appendix B. Changelog
B.1. Changes to version 02
o Include the support for source routing. o Include the support for source routing.
o Bring some features from [RFC6997], e.g., choice between hop-by- o Import some features from [RFC6997], e.g., choice between hop-by-
hop and source routing, duration of residence in the DAG, MaxRank, hop and source routing, the "L" bit which determines the duration
etc. of residence in the DAG, MaxRank, etc.
o Define new target option for AODV-RPL, including the Destination o Define new target option for AODV-RPL, including the Destination
Sequence Number in it. Move the TargNode address in RREQ option Sequence Number in it. Move the TargNode address in RREQ option
and the OrigNode address in RREP option into ADOV-RPL Target and the OrigNode address in RREP option into ADOV-RPL Target
Option. Option.
o Support route discovery for multiple targets in one RREQ-DIO. o Support route discovery for multiple targets in one RREQ-DIO.
o New InstanceID pairing mechanism. o New InstanceID pairing mechanism.
B.2. Changes to version 03
o Updated RREP option format. Remove the 'T' bit in RREP option.
o Using the same RPLInstanceID for RREQ and RREP, no need to update
[RFC6550].
o Explanation of Shift field in RREP.
o Multiple target options handling during transmission.
Authors' Addresses Authors' Addresses
Satish Anamalamudi Satish Anamalamudi
Huaiyin Institute of Technology SRM University-AP
No.89 North Beijing Road, Qinghe District Amaravati Campus
Huaian 223001 Amaravati, Andhra Pradesh 522 502
China India
Email: satishnaidu80@gmail.com Email: satishnaidu80@gmail.com
Mingui Zhang Mingui Zhang
Huawei Technologies Huawei Technologies
No. 156 Beiqing Rd. Haidian District No. 156 Beiqing Rd. Haidian District
Beijing 100095 Beijing 100095
China China
Email: zhangmingui@huawei.com Email: zhangmingui@huawei.com
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