--- 1/draft-ietf-roll-aodv-rpl-05.txt 2019-03-07 17:13:46.886573234 -0800 +++ 2/draft-ietf-roll-aodv-rpl-06.txt 2019-03-07 17:13:47.046577149 -0800 @@ -1,25 +1,25 @@ ROLL S. Anamalamudi Internet-Draft SRM University-AP Intended status: Standards Track M. Zhang -Expires: April 21, 2019 Huawei Technologies +Expires: September 8, 2019 Huawei Technologies C. Perkins Futurewei S.V.R.Anand Indian Institute of Science B. Liu Huawei Technologies - October 18, 2018 + March 7, 2019 Asymmetric AODV-P2P-RPL in Low-Power and Lossy Networks (LLNs) - draft-ietf-roll-aodv-rpl-05 + draft-ietf-roll-aodv-rpl-06 Abstract Route discovery for symmetric and asymmetric Point-to-Point (P2P) traffic flows is a desirable feature in Low power and Lossy Networks (LLNs). For that purpose, this document specifies a reactive P2P route discovery mechanism for both hop-by-hop routing and source routing: Ad Hoc On-demand Distance Vector Routing (AODV) based RPL protocol. Paired Instances are used to construct directional paths, in case some of the links between source and target node are @@ -33,25 +33,25 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on April 21, 2019. + This Internet-Draft will expire on September 8, 2019. Copyright Notice - Copyright (c) 2018 IETF Trust and the persons identified as the + Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as @@ -76,87 +76,92 @@ 6.3.1. RREP-DIO for Symmetric route . . . . . . . . . . . . 16 6.3.2. RREP-DIO for Asymmetric Route . . . . . . . . . . . . 16 6.3.3. RPLInstanceID Pairing . . . . . . . . . . . . . . . . 16 6.4. Receiving and Forwarding Route Reply . . . . . . . . . . 17 7. Gratuitous RREP . . . . . . . . . . . . . . . . . . . . . . . 18 8. Operation of Trickle Timer . . . . . . . . . . . . . . . . . 19 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 9.1. New Mode of Operation: AODV-RPL . . . . . . . . . . . . . 19 9.2. AODV-RPL Options: RREQ, RREP, and Target . . . . . . . . 19 10. Security Considerations . . . . . . . . . . . . . . . . . . . 20 - 11. Future Work . . . . . . . . . . . . . . . . . . . . . . . . . 20 - 12. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 20 - 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 + 11. Future Work . . . . . . . . . . . . . . . . . . . . . . . . . 21 + 12. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 21 + 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 21 13.1. Normative References . . . . . . . . . . . . . . . . . . 21 13.2. Informative References . . . . . . . . . . . . . . . . . 22 - Appendix A. Example: ETX/RSSI Values to select S bit . . . . . . 22 - Appendix B. Changelog . . . . . . . . . . . . . . . . . . . . . 23 - B.1. Changes to version 02 . . . . . . . . . . . . . . . . . . 23 - B.2. Changes to version 03 . . . . . . . . . . . . . . . . . . 23 - B.3. Changes to version 04 . . . . . . . . . . . . . . . . . . 24 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24 + Appendix A. Example: ETX/RSSI Values to select S bit . . . . . . 23 + Appendix B. Changelog . . . . . . . . . . . . . . . . . . . . . 24 + B.1. Changes from version 05 to version 06 . . . . . . . . . . 24 + B.2. Changes from version 04 to version 05 . . . . . . . . . . 24 + B.3. Changes from version 03 to version 04 . . . . . . . . . . 24 + B.4. Changes from version 02 to version 03 . . . . . . . . . . 24 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25 1. Introduction - RPL[RFC6550] is a IPv6 distance vector routing protocol for Low-power - and Lossy Networks (LLNs), and is designed to support multiple - traffic flows through a root-based Destination-Oriented Directed - Acyclic Graph (DODAG). Typically, a router does not have routing - information for most other routers. Consequently, for 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 - traverse a common ancestor in storing mode. Such P2P traffic is - thereby likely to traverse longer routes and may suffer severe - congestion near the DAG root [RFC6997], [RFC6998]. + RPL[RFC6550] (Routing Protocol for LLNs (Low-Power and Lossy + Networks)) is a IPv6 distance vector routing protocol designed to + support multiple traffic flows through a root-based Destination- + Oriented Directed Acyclic Graph (DODAG). Typically, a router does + not have routing information for most other routers. Consequently, + for 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 traverse a common ancestor in storing mode. Such + P2P traffic is thereby likely to traverse longer routes and may + suffer severe congestion near the DAG root [RFC6997], [RFC6998]. To discover better paths for P2P traffic flows in RPL, P2P-RPL [RFC6997] specifies a temporary DODAG where the source acts as a temporary root. The source initiates DIOs encapsulating the P2P 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 intermediate router adds its IP address and multicasts the P2P mode - DIOs, until the message reaches the target node (TargNode), which - then sends the "Discovery Reply" object. P2P-RPL is efficient for - source routing, but much less efficient for hop-by-hop routing due to - the extra address vector overhead. However, for symmetric links, - when the P2P mode DIO message is being multicast from the source hop- - by-hop, receiving nodes can infer a next hop towards the source. - When TargNode subsequently replies to the source along the - established forward route, receiving nodes determine the next hop - towards TargNode. For hop-by-hop routes (H=1) over symmetric links, - this would allow efficient use of routing tables for P2P-RDO messages + DIOs, until the message reaches the Target Node, which then sends the + "Discovery Reply" object. P2P-RPL is efficient for source routing, + but much less efficient for hop-by-hop routing due to the extra + address vector overhead. However, for symmetric links, when the P2P + mode DIO message is being multicast from the source hop-by-hop, + receiving nodes can infer a next hop towards the source. When the + Target Node subsequently replies to the source along the established + forward route, receiving nodes determine the next hop towards the + Target Node. For hop-by-hop routes (H=1) over symmetric links, this + would allow efficient use of routing tables for P2P-RDO messages instead of the "Address Vector". 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 the constraints of the objective function. This disallows the use of asymmetric links which are qualified in one direction. But, application-specific routing requirements as defined in IETF ROLL Working Group [RFC5548], [RFC5673], [RFC5826] and [RFC5867] may be satisfied by routing paths using bidirectional asymmetric links. For this purpose, [I-D.thubert-roll-asymlink] described bidirectional asymmetric links for RPL [RFC6550] with Paired DODAGs, for which the DAG root (DODAGID) is common for two Instances. This can satisfy application-specific routing requirements for bidirectional asymmetric links in core RPL [RFC6550]. Using P2P-RPL twice with Paired DODAGs, on the other hand, requires two roots: one for the source and another for the target node due to temporary DODAG formation. For networks composed of bidirectional asymmetric links (see Section 5), AODV-RPL specifies P2P route discovery, utilizing RPL with a new MoP. AODV-RPL makes use of two multicast messages to - discover possibly asymmetric routes, which can achieve higher route - diversity. AODV-RPL eliminates the need for address vector overhead - in hop-by-hop mode. This significantly reduces the control packet - size, which is important for Constrained LLN networks. Both + discover possibly asymmetric routes. This provides higher route + diversity and can find suitable routes that might otherwise go + undetected by RPL. AODV-RPL eliminates the need for address vector + overhead in hop-by-hop mode. This significantly reduces the control + packet size, which is important for Constrained LLN networks. Both discovered routes (upward and downward) meet the application specific metrics and constraints that are defined in the Objective Function - for each Instance [RFC6552]. + for each Instance [RFC6552]. On the other hand, the point-to-point + nature of routes discovered by AODV-RPL can reduce interference near + the root nodes and also provide routes with fewer hops, likely + improving performance in the network. The route discovery process in AODV-RPL is modeled on the analogous procedure specified in AODV [RFC3561]. The on-demand nature of AODV 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 messages, namely RREQ for Route Request, and RREP for Route Reply. AODV-RPL currently omits some features compared to AODV -- in particular, flagging Route Errors, blacklisting unidirectional links, multihoming, and handling unnumbered interfaces. @@ -250,21 +255,21 @@ Upward Route A route in the upward direction. ART option AODV-RPL Target option: a target option defined in this document. 3. Overview of AODV-RPL With AODV-RPL, routes from OrigNode to TargNode within the LLN - network established are "on-demand". In other words, the route + network are established "on-demand". In other words, the route discovery mechanism in AODV-RPL is invoked reactively when OrigNode has data for delivery to the TargNode but existing routes do not satisfy the application's requirements. The routes discovered by AODV-RPL are not constrained to traverse a common ancestor. Unlike RPL [RFC6550] and P2P-RPL [RFC6997], AODV-RPL can enable asymmetric communication paths in networks with bidirectional asymmetric links. For this purpose, AODV-RPL enables discovery of two routes: namely, one from OrigNode to TargNode, and another from TargNode to OrigNode. When possible, AODV-RPL also enables symmetric route discovery along Paired DODAGs (see Section 5). @@ -576,25 +581,25 @@ OrigNode has data to be transmitted to the TargNode, but does not have a route for the target that fulfills the requirements of the data transmission. In this case, the OrigNode builds a local RPLInstance and a DODAG rooted at itself. Then it transmits a DIO message containing exactly one RREQ option (see Section 4.1) via link-local multicast. The DIO MUST contain at least one ART Option (see Section 4.3). The 'S' bit in RREQ-DIO sent out by the OrigNode is set to 1. Each node maintains a sequence number, which rolls over like a - lollipop counter [Perlman83], detailed operation can refer to the - section 7.2 of [RFC6550]. When the OrigNode initiates a route - discovery process, it MUST increse its own sequence number to avoid - conflicts with previous established routes. The increased number is - carried in the OrigSeqNo field of the RREQ option. + lollipop counter [Perlman83]; refer to section 7.2 of [RFC6550] for + detailed operation. When the OrigNode initiates a route discovery + process, it MUST increase its own sequence number to avoid conflicts + with previously established routes. The sequence number is carried + in the OrigSeqNo field of the RREQ option. The address in the ART Option can be a unicast IPv6 address or a prefix. The OrigNode can initiate the route discovery process for multiple targets simultaneously by including multiple ART Options, and within a RREQ-DIO the requirements for the routes to different TargNodes MUST be the same. OrigNode can maintain different RPLInstances to discover routes with different requirements to the same targets. Using the InstanceID pairing mechanism (see Section 6.3.3), route replies (RREP-DIOs) for @@ -642,23 +647,23 @@ Step 3: If the 'H' bit is set to 1, then the router (TargNode or intermediate) MUST build the upward route entry accordingly. The route entry MUST include at least the following items: Source Address, InstanceID, Destination Address, Next Hop, Lifetime, and Sequence Number. The Destination Address and the InstanceID can be respectively learned from the DODAGID and the RPLInstanceID of the RREQ-DIO, and the Source Address is copied from the ART - 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. The sequence number represents the + Option. The next hop is the preferred parent. The lifetime is + set according to DODAG configuration and can be extended when 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 the address of the interface receiving the RREQ-DIO into the address vector. Step 4: @@ -700,26 +705,24 @@ implementation-specific and out of scope. If the implementation uses the symmetric route, the TargNode MAY delay transmitting the RREP-DIO for duration RREP_WAIT_TIME to await a better symmetric route. 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 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 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. - The sequence number of the TargNode is updated to the maximum of its - current sequence number and the Dest SeqNo in the ART option of the - 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. + TargNode increments its current sequence number and uses the + incremented result in the Dest SeqNo in the ART option of the RREQ- + DIO. 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 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 order to discover the downstream route from the OrigNode to the TargNode. The RREP-DIO message MUST be re-transmitted via link-local multicast until the OrigNode is reached or MaxRank is exceeded. The settings of the fields in RREP option and ART option are the same @@ -885,22 +888,58 @@ +-------------+------------------------+---------------+ | TBD3 (0x0B) | RREP Option | This document | +-------------+------------------------+---------------+ | TBD3 (0x0C) | ART Option | This document | +-------------+------------------------+---------------+ Figure 7: AODV-RPL Options 10. Security Considerations - This document does not introduce additional security issues compared - to base RPL. For general RPL security considerations, see [RFC6550]. + The security mechanisms defined in section 10 of [RFC6550] and + section 11 of [RFC6997] can also be applied to the control messages + defined in this specification. The RREQ-DIO and RREP-DIO both have a + secure variant, which provide integrity and replay protection as well + as optional confidentiality and delay protection. + + AODV-RPL can operate in the three security modes defined in + [RFC6550]. AODV-RPL messages SHOULD use a security mode at least as + strong as the security mode used in RPL. + + o Unsecured. In this mode, RREQ-DIO and RREP-DIO are used without + any security fields as defined in section 6.1 of [RFC6550]. The + control messages can be protected by other security mechanisms, + e.g. link-layer security. This mode SHOULD NOT be used when RPL + is using Preinstalled mode or Authenticated mode (see below). + + o Preinstalled. In this mode, AODV-RPL uses secure RREQ-DIO and + RREP-DIO messages, and a node wishing to join a secured network + will have been pre-configured with a shared key. A node can use + that key to join the AODV-RPL DODAG as a host or a router. + Unsecured messages MUST be dropped. This mode SHOULD NOT be used + when RPL is using Authenticated mode. + + o Authenticated. In this mode, besides the preinstalled shared key, + a node MUST obtain a second key from a key authority. The + interaction between a node and the key authority is out of scope + for this specification. Authenticated mode may be useful, for + instance, to protect against a malicious rogue router advertising + false information in RREQ-DIO or RREP-DIO to include itself in the + discovered route. This mode would also prevent a malicious router + from initiating route discovery operations or launching denial-of- + service attacks to impair the performance of the LLN. AODV-RPL + can use the keys established with the Authenticated mode RPL + instance. Once a router or a host has been authenticated in the + RPL instance, it can join the AODV-RPL instance without any + further authentication. The authentication in AODV-RPL can also + be independent to RPL if, before joining the AODV-RPL instance, + the node obtains another key from the key authority. 11. Future Work There has been some discussion about how to determine the initial state of a link after an AODV-RPL-based network has begun operation. The current draft operates as if the links are symmetric until additional metric information is collected. The means for making link metric information is considered out of scope for AODV-RPL. In the future, RREQ and RREP messages could be equipped with new fields for use in verifying link metrics. In particular, it is possible to @@ -927,40 +967,20 @@ [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3561] Perkins, C., Belding-Royer, E., and S. Das, "Ad hoc On- Demand Distance Vector (AODV) Routing", RFC 3561, DOI 10.17487/RFC3561, July 2003, . - [RFC5548] Dohler, M., Ed., Watteyne, T., Ed., Winter, T., Ed., and - D. Barthel, Ed., "Routing Requirements for Urban Low-Power - and Lossy Networks", RFC 5548, DOI 10.17487/RFC5548, May - 2009, . - - [RFC5673] Pister, K., Ed., Thubert, P., Ed., Dwars, S., and T. - Phinney, "Industrial Routing Requirements in Low-Power and - Lossy Networks", RFC 5673, DOI 10.17487/RFC5673, October - 2009, . - - [RFC5826] Brandt, A., Buron, J., and G. Porcu, "Home Automation - Routing Requirements in Low-Power and Lossy Networks", - RFC 5826, DOI 10.17487/RFC5826, April 2010, - . - - [RFC5867] Martocci, J., Ed., De Mil, P., Riou, N., and W. Vermeylen, - "Building Automation Routing Requirements in Low-Power and - Lossy Networks", RFC 5867, DOI 10.17487/RFC5867, June - 2010, . - [RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J., Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, JP., and R. Alexander, "RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks", RFC 6550, DOI 10.17487/RFC6550, March 2012, . [RFC6552] Thubert, P., Ed., "Objective Function Zero for the Routing Protocol for Low-Power and Lossy Networks (RPL)", RFC 6552, DOI 10.17487/RFC6552, March 2012, @@ -976,20 +996,40 @@ [I-D.thubert-roll-asymlink] Thubert, P., "RPL adaptation for asymmetrical links", draft-thubert-roll-asymlink-02 (work in progress), December 2011. [Perlman83] Perlman, R., "Fault-Tolerant Broadcast of Routing Information", December 1983. + [RFC5548] Dohler, M., Ed., Watteyne, T., Ed., Winter, T., Ed., and + D. Barthel, Ed., "Routing Requirements for Urban Low-Power + and Lossy Networks", RFC 5548, DOI 10.17487/RFC5548, May + 2009, . + + [RFC5673] Pister, K., Ed., Thubert, P., Ed., Dwars, S., and T. + Phinney, "Industrial Routing Requirements in Low-Power and + Lossy Networks", RFC 5673, DOI 10.17487/RFC5673, October + 2009, . + + [RFC5826] Brandt, A., Buron, J., and G. Porcu, "Home Automation + Routing Requirements in Low-Power and Lossy Networks", + RFC 5826, DOI 10.17487/RFC5826, April 2010, + . + + [RFC5867] Martocci, J., Ed., De Mil, P., Riou, N., and W. Vermeylen, + "Building Automation Routing Requirements in Low-Power and + Lossy Networks", RFC 5867, DOI 10.17487/RFC5867, June + 2010, . + [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, . Appendix A. Example: ETX/RSSI Values to select S bit We have tested the combination of "RSSI(downstream)" and "ETX (upstream)" to determine whether the link is symmetric or asymmetric @@ -1025,55 +1065,65 @@ models, one can determine a relationship between RSSI and ETX representable as an expression or a mapping table. Such a relationship in turn can be used to estimate ETX value at nodeA for link NodeB--->NodeA from the received RSSI from NodeB. Whenever 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 NodeA to Destination is asymmetric with "S" bit remains to "0". Appendix B. Changelog -B.1. Changes to version 02 +B.1. Changes from version 05 to version 06 - o Include the support for source routing. + o Added Security Considerations based on the security mechanisms + defined in RFC 6550. - o Import some features from [RFC6997], e.g., choice between hop-by- - hop and source routing, the "L" bit which determines the duration - of residence in the DAG, MaxRank, etc. + o Clarified the nature of improvements due to P2P route discovery + versus bidirectional asymmetric route discovery. - o Define new target option for AODV-RPL, including the Destination - Sequence Number in it. Move the TargNode address in RREQ option - and the OrigNode address in RREP option into ADOV-RPL Target - Option. + o Editorial improvements and corrections. - o Support route discovery for multiple targets in one RREQ-DIO. +B.2. Changes from version 04 to version 05 - o New InstanceID pairing mechanism. + o Add description for sequence number operations. -B.2. Changes to version 03 + o Extend the residence duration L in section 4.1. + + o Change AODV-RPL Target option to ART option. + +B.3. Changes from version 03 to version 04 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. -B.3. Changes to version 04 +B.4. Changes from version 02 to version 03 - o Add description for sequence number operations. + o Include the support for source routing. - o Extend the residence duration L in the section 4.1. + o Import some features from [RFC6997], e.g., choice between hop-by- + hop and source routing, the "L" bit which determines the duration + of residence in the DAG, MaxRank, etc. - o Change AODV-RPL Target option to ART option. + o Define new target option for AODV-RPL, including the Destination + Sequence Number in it. Move the TargNode address in RREQ option + and the OrigNode address in RREP option into ADOV-RPL Target + Option. + + o Support route discovery for multiple targets in one RREQ-DIO. + + o New InstanceID pairing mechanism. Authors' Addresses Satish Anamalamudi SRM University-AP Amaravati Campus Amaravati, Andhra Pradesh 522 502 India Email: satishnaidu80@gmail.com @@ -1083,27 +1133,28 @@ No. 156 Beiqing Rd. Haidian District Beijing 100095 China Email: zhangmingui@huawei.com Charles E. Perkins Futurewei 2330 Central Expressway Santa Clara 95050 - Unites States + United States Email: charliep@computer.org S.V.R Anand Indian Institute of Science Bangalore 560012 India Email: anand@ece.iisc.ernet.in + Bing Liu Huawei Technologies No. 156 Beiqing Rd. Haidian District Beijing 100095 China Email: remy.liubing@huawei.com