draft-ietf-roll-aodv-rpl-04.txt   draft-ietf-roll-aodv-rpl-05.txt 
ROLL S. Anamalamudi ROLL S. Anamalamudi
Internet-Draft SRM University-AP Internet-Draft SRM University-AP
Intended status: Standards Track M. Zhang Intended status: Standards Track M. Zhang
Expires: January 3, 2019 Huawei Technologies Expires: April 21, 2019 Huawei Technologies
AR. Sangi
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
July 2, 2018 October 18, 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-04 draft-ietf-roll-aodv-rpl-05
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
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 3, 2019. This Internet-Draft will expire on April 21, 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
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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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. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 20
12.1. Normative References . . . . . . . . . . . . . . . . . . 20 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
12.2. Informative References . . . . . . . . . . . . . . . . . 21 13.1. Normative References . . . . . . . . . . . . . . . . . . 21
Appendix A. Example: ETX/RSSI Values to select S bit . . . . . . 21 13.2. Informative References . . . . . . . . . . . . . . . . . 22
Appendix B. Changelog . . . . . . . . . . . . . . . . . . . . . 22 Appendix A. Example: ETX/RSSI Values to select S bit . . . . . . 22
B.1. Changes to version 02 . . . . . . . . . . . . . . . . . . 22 Appendix B. Changelog . . . . . . . . . . . . . . . . . . . . . 23
B.1. Changes to version 02 . . . . . . . . . . . . . . . . . . 23
B.2. Changes to version 03 . . . . . . . . . . . . . . . . . . 23 B.2. Changes to version 03 . . . . . . . . . . . . . . . . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23 B.3. Changes to version 04 . . . . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24
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
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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.
ART option
AODV-RPL Target option: a target option defined in this document.
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 not constrained to traverse a common ancestor. Unlike AODV-RPL are not constrained to traverse a common ancestor. Unlike
RPL [RFC6550] and P2P-RPL [RFC6997], AODV-RPL can enable asymmetric RPL [RFC6550] and P2P-RPL [RFC6997], AODV-RPL can enable asymmetric
communication paths in networks with bidirectional asymmetric links. communication paths in networks with bidirectional asymmetric links.
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2-bit unsigned integer determining the duration that a node is 2-bit unsigned integer determining the duration that a node is
able to belong to the temporary DAG in RREQ-Instance, including able to belong to the temporary DAG in RREQ-Instance, including
the OrigNode and the TargNode. Once the time is reached, a node 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 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 the temporary DODAG. The definition for the "L" bit is similar to
that found in [RFC6997], except that the values are adjusted to that found in [RFC6997], except that the values are adjusted to
enable arbitrarily long route lifetime. enable arbitrarily long route lifetime.
* 0x00: No time limit imposed. * 0x00: No time limit imposed.
* 0x01: 2 seconds * 0x01: 16 seconds
* 0x02: 16 seconds * 0x02: 64 seconds
* 0x03: 64 seconds * 0x03: 256 seconds
L is independent from the route lifetime, which is defined in the L is independent from the route lifetime, which is defined in the
DODAG configuration option. The route entries in hop-by-hop DODAG configuration option. The route entries in hop-by-hop
routing and states of source routing can still be maintained even routing and states of source routing can 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 (calculated using the DAGRank() macro defined in [RFC6550]). rank (calculated using the DAGRank() macro defined in [RFC6550]).
A value of 0 in this field indicates the limit is infinity. A value of 0 in this field indicates the limit is infinity.
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Address Vector Address Vector
Only present when the 'H' bit is set to 0. For an asymmetric Only present when the 'H' bit is set to 0. For an asymmetric
route, the Address Vector represents the IPv6 addresses of the route, the Address Vector represents the IPv6 addresses of the
route that the RREP-DIO has passed. For a symmetric route, it is route that the RREP-DIO has passed. For a symmetric route, it is
the Address Vector when the RREQ-DIO arrives at the TargNode, the Address Vector when the RREQ-DIO arrives at the TargNode,
unchanged during the transmission to the OrigNode. 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 (ART) Option is defined based on the Target
core RPL [RFC6550]: the Destination Sequence Number of the TargNode Option in core RPL [RFC6550]: the Destination Sequence Number of the
is added. TargNode is added.
A RREQ-DIO message MUST carry at least one AODV-RPL Target Options. A RREQ-DIO message MUST carry at least one ART Options. A RREP-DIO
A RREP-DIO message MUST carry exactly one AODV-RPL Target Option. message MUST carry exactly one ART Option.
OrigNode can include multiple TargNode addresses via multiple AODV- OrigNode can include multiple TargNode addresses via multiple AODV-
RPL Target Options in the RREQ-DIO, for routes that share the same RPL Target Options in the RREQ-DIO, for routes that share the same
constraints. This reduces the cost to building only one DODAG. constraints. This reduces the cost to building only one DODAG.
Furthermore, a single Target Option can be used for different Furthermore, a single Target Option can be used for different
TargNode addresses if they share the same prefix; in that case the TargNode addresses if they share the same prefix; in that case the
use of the destination sequence number is not defined in this use of the destination sequence number is not defined in this
document. document.
0 1 2 3 0 1 2 3
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| | | |
+ | + |
| 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 assigned to the AODV-RPL Target Option The type assigned to the ART Option
Dest SeqNo 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 Border Router, O is the OrigNode, In Figure 4 and Figure 5, BR is the Border Router, O is the OrigNode,
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6. AODV-RPL Operation 6. AODV-RPL Operation
6.1. Route Request Generation 6.1. Route Request Generation
The route discovery process is initiated when an application at the The route discovery process is initiated when an application at the
OrigNode has data to be transmitted to the TargNode, but does not OrigNode has data to be transmitted to the TargNode, but does not
have a route for the target that fulfills the requirements of the have a route for the target that fulfills the requirements of the
data transmission. In this case, the OrigNode builds a local data transmission. In this case, the OrigNode builds a local
RPLInstance and a DODAG rooted at itself. Then it transmits a DIO RPLInstance and a DODAG rooted at itself. Then it transmits a DIO
message containing exactly one RREQ option (see Section 4.1) via message containing exactly one RREQ option (see Section 4.1) via
link-local multicast. The DIO MUST contain at least one AODV-RPL link-local multicast. The DIO MUST contain at least one ART Option
Target Option (see Section 4.3). The 'S' bit in RREQ-DIO sent out by (see Section 4.3). The 'S' bit in RREQ-DIO sent out by the OrigNode
the OrigNode is set to 1. is set to 1.
The OrigNode maintains its Sequence Number as defined in AODV Each node maintains a sequence number, which rolls over like a
[RFC3561]. Namely, the OrigNode increments its Sequence number each lollipop counter [Perlman83], detailed operation can refer to the
time it initiate a new route discovery operation by transmitting a section 7.2 of [RFC6550]. When the OrigNode initiates a route
new RREQ message. Similarly, TargNode increments its Sequence number discovery process, it MUST increse its own sequence number to avoid
each time it transmits a RREP message in response to a new RREQ conflicts with previous established routes. The increased number is
message (one with an incremented Sequence Number for OrigNode). carried in the OrigSeqNo field of the RREQ option.
The address in the AODV-RPL Target Option can be a unicast IPv6 The address in the ART Option can be a unicast IPv6 address or a
address, or a prefix. The OrigNode can initiate the route discovery prefix. The OrigNode can initiate the route discovery process for
process for multiple targets simultaneously by including multiple multiple targets simultaneously by including multiple ART Options,
AODV-RPL Target Options, and within a RREQ-DIO the requirements for and within a RREQ-DIO the requirements for the routes to different
the routes to different TargNodes MUST be the same. TargNodes MUST be the same.
OrigNode can maintain different RPLInstances to discover routes with OrigNode can maintain different RPLInstances to discover routes with
different requirements to the same targets. Using the InstanceID different requirements to the same targets. Using the InstanceID
pairing mechanism (see Section 6.3.3), route replies (RREP-DIOs) for pairing mechanism (see Section 6.3.3), route replies (RREP-DIOs) for
different RPLInstances can be distinguished. different RPLInstances can be distinguished.
The transmission of RREQ-DIO obeys the Trickle timer. If the The transmission of RREQ-DIO obeys the Trickle timer. If the
duration specified by the "L" bit has elapsed, the OrigNode MUST duration specified by the "L" bit has elapsed, the OrigNode MUST
leave the DODAG and stop sending RREQ-DIOs in the related leave the DODAG and stop sending RREQ-DIOs in the related
RPLInstance. RPLInstance.
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is selected as the preferred parent. Later, other RREQ-DIO is selected as the preferred parent. Later, other RREQ-DIO
messages might be received. How to maintain the parent set, messages might be received. How to maintain the parent set,
select the preferred parent, and update the router's rank obeys 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 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 constraint or the MaxRank limit is not fulfilled, the router MUST
discard the received RREQ-DIO and MUST NOT join the DODAG. 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. If so, this router is one of the of the ART Options. 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 the upward route entry accordingly. The intermediate) MUST build the upward route entry accordingly. The
route entry MUST include at least the following items: Source route entry MUST include at least the following items: Source
Address, InstanceID, Destination Address, Next Hop and Lifetime. Address, InstanceID, Destination Address, Next Hop, Lifetime, and
The Destination Address and the InstanceID can be respectively Sequence Number. The Destination Address and the InstanceID can
learned from the DODAGID and the RPLInstanceID of the RREQ-DIO, be respectively learned from the DODAGID and the RPLInstanceID of
and the Source Address is copied from the AODV-RPL Target Option. the RREQ-DIO, and the Source Address is copied from the ART
The next hop is the preferred parent. And the lifetime is set Option. The next hop is the preferred parent. And the lifetime
according to DODAG configuration and can be extended when the is set according to DODAG configuration and can be extended when
route is actually used. the route is actually used. The sequence number represents the
freshness of the route entry, and it is copied from the Orig SeqNo
field of the RREQ option. A route entry with same source and
destination address, same InstanceID, but stale sequence number,
SHOULD be deleted.
If the 'H' bit is set to 0, an intermediate router MUST include If the 'H' bit is set to 0, an intermediate router MUST include
the address of the interface receiving the RREQ-DIO into the the address of the interface receiving the RREQ-DIO into the
address vector. address vector.
Step 4: Step 4:
An intermediate router transmits a RREQ-DIO via link-local An intermediate router transmits a RREQ-DIO via link-local
multicast. TargNode prepares a RREP-DIO. multicast. TargNode prepares a RREP-DIO.
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An intermediate router could receive several RREQ-DIOs from routers An intermediate router could receive several RREQ-DIOs from routers
with lower ranks in the same RREQ-instance but have different lists with lower ranks in the same RREQ-instance but have different lists
of Target Options. When rebroadcasting the RREQ-DIO, the of Target Options. When rebroadcasting the RREQ-DIO, the
intersection of these lists SHOULD be included. For example, suppose intersection of these lists SHOULD be included. For example, suppose
two RREQ-DIOs are received with the same RPLInstance and OrigNode. two RREQ-DIOs are received with the same RPLInstance and OrigNode.
Suppose further that the first RREQ has (T1, T2) as the targets, and 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 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 included in the generated RREQ-DIO. If the intersection is empty, it
means that all the targets have been reached, and the router SHOULD 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- NOT send out any RREQ-DIO. Any RREQ-DIO message with different ART
RPL Target Options coming from a router with higher rank is ignored. Options coming from a router with higher rank is ignored.
6.3. Generating Route Reply (RREP) at TargNode 6.3. Generating Route Reply (RREP) at TargNode
6.3.1. RREP-DIO for Symmetric route 6.3.1. RREP-DIO for Symmetric route
If a RREQ-DIO arrives at TargNode with the 'S' bit set to 1, there is If a RREQ-DIO arrives at TargNode with the 'S' bit set to 1, there is
a symmetric route along which both directions can fulfill the a symmetric route along which both directions can fulfill the
requirements. Other RREQ-DIOs might later provide asymmetric upward requirements. Other RREQ-DIOs might later provide asymmetric upward
routes (i.e. S=0). Selection between a qualified symmetric route routes (i.e. S=0). Selection between a qualified symmetric route
and an asymmetric route that might have better performance is and an asymmetric route that might have better performance is
implementation-specific and out of scope. If the implementation uses implementation-specific and out of scope. If the implementation uses
the symmetric route, the TargNode MAY delay transmitting the RREP-DIO the symmetric route, the TargNode MAY delay transmitting the RREP-DIO
for duration RREP_WAIT_TIME to await a better symmetric route. for duration RREP_WAIT_TIME to await a better symmetric route.
For a symmetric route, the RREP-DIO message is unicast to the next For a symmetric route, the RREP-DIO message is unicast to the next
hop according to the accumulated address vector (H=0) or the route hop according to the accumulated address vector (H=0) or the route
entry (H=1). Thus the DODAG in RREP-Instance does not need to be entry (H=1). Thus the DODAG in RREP-Instance does not need to be
built. The RPLInstanceID in the RREP-Instance is paired as defined built. The RPLInstanceID in the RREP-Instance is paired as defined
in Section 6.3.3. In case the 'H' bit is set to 0, the address in Section 6.3.3. In case the 'H' bit is set to 0, the address
vector received in the RREQ-DIO MUST be included in the RREP-DIO. vector received in the RREQ-DIO MUST be included in the RREP-DIO.
The address of the OrigNode MUST be encapsulated in an AODV-RPL The sequence number of the TargNode is updated to the maximum of its
Target Option and included in this RREP-DIO message, and the Dest current sequence number and the Dest SeqNo in the ART option of the
SeqNo is incremented, as is done in AODV [RFC3561]. RREQ-DIO, using a mechanism similar to that used in [RFC3561]. This
updated sequence number is then copied to the Dest SeqNo field of the
ART option. The address of the OrigNode MUST be encapsulated in the
ART Option and included in this RREP-DIO message.
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 re-transmitted via link-local TargNode. The RREP-DIO message MUST be re-transmitted via link-local
multicast until the OrigNode is reached or MaxRank is exceeded. multicast until the OrigNode is reached or MaxRank is exceeded.
The settings of the fields in RREP option are the same as in The settings of the fields in RREP option and ART option are the same
symmetric route except for the 'S' bit. as for the 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 (OrigNode, TargNode, RPLInstanceID) is needed to uniquely tuple (OrigNode, TargNode, RPLInstanceID) is needed to uniquely
identify a discovered route. The upper layer applications may have identify a discovered route. The upper layer applications may have
different requirements and they can initiate the route discoveries different requirements and they can initiate the route discoveries
simultaneously. Thus between the same pair of OrigNode and TargNode, simultaneously. Thus between the same pair of OrigNode and TargNode,
there can be multiple AODV-RPL instances. To avoid any mismatch, the there can be multiple AODV-RPL instances. To avoid any mismatch, the
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update the router's rank obeys the core RPL and the OFs defined in update the router's rank obeys the core RPL and the OFs defined in
ROLL WG. ROLL WG.
If the constraints are not fulfilled, the router MUST NOT join the If the constraints are not fulfilled, the router MUST NOT join the
DODAG; the router MUST discard the RREQ-DIO, and does not execute DODAG; the router MUST discard the RREQ-DIO, and does not execute
the remaining steps in this section. the remaining steps in this section.
Step 2: Step 2:
The router next 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 ART Option. If so, this router is the OrigNode of the route
route discovery. Otherwise, it is an intermediate router. 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 a downward route entry. The route entry intermediate) MUST build a downward route entry. The route entry
SHOULD include at least the following items: OrigNode Address, SHOULD include at least the following items: OrigNode Address,
InstanceID, TargNode Address as destination, Next Hop and InstanceID, TargNode Address as destination, Next Hop, Lifetime
Lifetime. For a symmetric route, the next hop in the route entry and Sequence Number. For a symmetric route, the next hop in the
is the router from which the RREP-DIO is received. For an route entry is the router from which the RREP-DIO is received.
asymmetric route, the next hop is the preferred parent in the For an asymmetric route, the next hop is the preferred parent in
DODAG of RREQ-Instance. The InstanceID in the route entry MUST be the DODAG of RREQ-Instance. The InstanceID in the route entry
the original RPLInstanceID (after subtracting the Shift field MUST be the original RPLInstanceID (after subtracting the Shift
value). The source address is learned from the AODV-RPL Target field value). The source address is learned from the ART Option,
Option, and the destination address is learned from the DODAGID. and the destination address is learned from the DODAGID. The
The lifetime is set according to DODAG configuration and can be lifetime is set according to DODAG configuration and can be
extended when the route is actually used. extended when the route is actually used. The sequence number
represents the freshness of the route entry, and is copied from
the Dest SeqNo field of the ART option of the RREP-DIO. A route
entry with same source and destination address, same InstanceID,
but stale sequence number, SHOULD be deleted.
If the 'H' bit is set to 0, for an asymmetric route, an If the 'H' bit is set to 0, for an asymmetric route, an
intermediate router MUST include the address of the interface intermediate router MUST include the address of the interface
receiving the RREP-DIO into the address vector; for a symmetric receiving the RREP-DIO into the address vector; for a symmetric
route, there is nothing to do in this step. route, there is nothing to do in this step.
Step 4: Step 4:
If the receiver is the OrigNode, it can start transmitting the If the receiver is the OrigNode, it can start transmitting the
application data to TargNode along the path as provided in RREP- application data to TargNode along the path as provided in RREP-
Instance, and processing for the RREP-DIO is complete. Otherwise, Instance, and processing for the RREP-DIO is complete. Otherwise,
in case of an asymmetric route, the intermediate router transmits in case of an asymmetric route, the intermediate router transmits
the RREP-DIO via link-local multicast. In case of a symmetric the RREP-DIO via link-local multicast. In case of a symmetric
route, the RREP-DIO message is unicast to the next hop according route, the RREP-DIO message is unicast to the next hop according
to the address vector in the RREP-DIO (H=0) or the local route 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 entry (H=1). The RPLInstanceID in the transmitted RREP-DIO is the
same as the value in the received RREP-DIO. same as the value in the received RREP-DIO. The local knowledge
for the TargNode's sequence number SHOULD be updated.
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 a more
downward and upward routes to T which also fulfill the requirements. recent (larger destination sequence number) pair of 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 upward the OrigNode O and the router R. Thus T can have a complete upward
route address vector from itself to O. Then R MUST send out the route address vector from itself to O. Then R MUST send out the
gratuitous RREP-DIO including the address vector from R to T. 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 hop-by-hop to T. The routers along the route SHOULD build new route
with the related RPLInstanceID and DODAGID in the downward direction. entries with the related RPLInstanceID and DODAGID in the downward
Then T MUST unicast the RREP-DIO to R, and the routers along the direction. Then T MUST unicast the RREP-DIO hop-by-hop to R, and the
route SHOULD build new route entries in the upward direction. Upon routers along the route SHOULD build new route entries in the upward
received the unicast RREP-DIO, R sends the gratuitous RREP-DIO to the direction. Upon receiving the unicast RREP-DIO, R sends the
OrigNode as the same way defined in Section 6.3. gratuitous RREP-DIO to the OrigNode as defined in Section 6.3.
8. Operation of Trickle Timer 8. Operation of Trickle Timer
The trickle timer operation to control RREQ-Instance/RREP-Instance The trickle timer operation to control RREQ-Instance/RREP-Instance
multicast is similar to that in P2P-RPL [RFC6997]. multicast is similar to that in P2P-RPL [RFC6997].
9. IANA Considerations 9. IANA Considerations
9.1. New Mode of Operation: AODV-RPL 9.1. New Mode of Operation: AODV-RPL
skipping to change at page 19, line 38 skipping to change at page 19, line 46
| Value | Description | Reference | | Value | Description | Reference |
+-------------+---------------+---------------+ +-------------+---------------+---------------+
| TBD1 (5) | AODV-RPL | This document | | TBD1 (5) | AODV-RPL | This document |
+-------------+---------------+---------------+ +-------------+---------------+---------------+
Figure 6: 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 "ART" with values of TBD2 (0x0A), TBD3 (0x0B) and TBD4 (0x0C)
TBD4 (0x0C) from the "RPL Control Message Options" space [RFC6550]. 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) | ART Option | This document |
+-------------+------------------------+---------------+ +-------------+------------------------+---------------+
Figure 7: 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
skipping to change at page 20, line 27 skipping to change at page 20, line 39
the future, RREQ and RREP messages could be equipped with new fields the future, RREQ and RREP messages could be equipped with new fields
for use in verifying link metrics. In particular, it is possible to for use in verifying link metrics. In particular, it is possible to
identify unidirectional links; an RREQ received across a identify unidirectional links; an RREQ received across a
unidirectional link has to be dropped, since the destination node unidirectional link has to be dropped, since the destination node
cannot make use of the received DODAG to route packets back to the cannot make use of the received DODAG to route packets back to the
source node that originated the route discovery operation. This is source node that originated the route discovery operation. This is
roughly the same as considering a unidirectional link to present an roughly the same as considering a unidirectional link to present an
infinite cost metric that automatically disqualifies it for use in infinite cost metric that automatically disqualifies it for use in
the reverse direction. the reverse direction.
12. References 12. Contributors
12.1. Normative References Abdur Rashid Sangi
Huaiyin Institute of Technology
No.89 North Beijing Road, Qinghe District
Huaian 223001
P.R. China
Email: sangi_bahrian@yahoo.com
13. References
13.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3561] Perkins, C., Belding-Royer, E., and S. Das, "Ad hoc On- [RFC3561] Perkins, C., Belding-Royer, E., and S. Das, "Ad hoc On-
Demand Distance Vector (AODV) Routing", RFC 3561, Demand Distance Vector (AODV) Routing", RFC 3561,
DOI 10.17487/RFC3561, July 2003, DOI 10.17487/RFC3561, July 2003,
<https://www.rfc-editor.org/info/rfc3561>. <https://www.rfc-editor.org/info/rfc3561>.
skipping to change at page 21, line 33 skipping to change at page 22, line 11
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>.
[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 13.2. 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.
[Perlman83]
Perlman, R., "Fault-Tolerant Broadcast of Routing
Information", December 1983.
[RFC6997] Goyal, M., Ed., Baccelli, E., Philipp, M., Brandt, A., and [RFC6997] Goyal, M., Ed., Baccelli, E., Philipp, M., Brandt, A., and
J. Martocci, "Reactive Discovery of Point-to-Point Routes J. Martocci, "Reactive Discovery of Point-to-Point Routes
in Low-Power and Lossy Networks", RFC 6997, in Low-Power and Lossy Networks", RFC 6997,
DOI 10.17487/RFC6997, August 2013, DOI 10.17487/RFC6997, August 2013,
<https://www.rfc-editor.org/info/rfc6997>. <https://www.rfc-editor.org/info/rfc6997>.
Appendix A. Example: ETX/RSSI Values to select S bit 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 determine whether the link is symmetric or asymmetric (upstream)" to determine whether the link is symmetric or asymmetric
at the intermediate nodes. The example of how the ETX and RSSI at the intermediate nodes. The example of how the ETX and RSSI
values are used in conjuction is explained below: values are used in conjuction is explained below:
Source---------->NodeA---------->NodeB------->Destination Source---------->NodeA---------->NodeB------->Destination
Figure 8: 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 | | > -60 | 150 |
| -25 to -15 | 192 | | -70 to -60 | 192 |
| -35 to -25 | 226 | | -80 to -70 | 226 |
| -45 to -35 | 662 | | -90 to -80 | 662 |
| -55 to -45 | 993 | | -100 to -90 | 993 |
+-------------------------+----------------------------------------+ +-------------------------+----------------------------------------+
Table 1: Selection of 'S' bit based on Expected ETX value Table 1: Selection of 'S' bit based on Expected ETX value
We tested the operations in this specification by making the We tested the operations in this specification by making the
following experiment, using the above parameters. In our experiment, following experiment, using the above parameters. In our experiment,
a communication link is considered as symmetric if the ETX value of a communication link is considered as symmetric if the ETX value of
NodeA->NodeB and NodeB->NodeA (See Figure.8) are, say, within 1:3 NodeA->NodeB and NodeB->NodeA (See Figure.8) are, say, within 1:3
ratio. This ratio should be taken as a notional metric for deciding ratio. This ratio should be taken as a notional metric for deciding
link symmetric/asymmetric nature, and precise definition of the ratio link symmetric/asymmetric nature, and precise definition of the ratio
skipping to change at page 23, line 20 skipping to change at page 24, line 5
o Updated RREP option format. Remove the 'T' bit in RREP option. 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 o Using the same RPLInstanceID for RREQ and RREP, no need to update
[RFC6550]. [RFC6550].
o Explanation of Shift field in RREP. o Explanation of Shift field in RREP.
o Multiple target options handling during transmission. o Multiple target options handling during transmission.
B.3. Changes to version 04
o Add description for sequence number operations.
o Extend the residence duration L in the section 4.1.
o Change AODV-RPL Target option to ART option.
Authors' Addresses Authors' Addresses
Satish Anamalamudi Satish Anamalamudi
SRM University-AP SRM University-AP
Amaravati Campus Amaravati Campus
Amaravati, Andhra Pradesh 522 502 Amaravati, Andhra Pradesh 522 502
India 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
Abdur Rashid Sangi
Huaiyin Institute of Technology
No.89 North Beijing Road, Qinghe District
Huaian 223001
P.R. China
Email: sangi_bahrian@yahoo.com
Charles E. Perkins Charles E. Perkins
Futurewei Futurewei
2330 Central Expressway 2330 Central Expressway
Santa Clara 95050 Santa Clara 95050
Unites States Unites States
Email: charliep@computer.org Email: charliep@computer.org
S.V.R Anand S.V.R Anand
Indian Institute of Science Indian Institute of Science
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