Routing MPR Optimization for the Optimized Link State Routing Protocol version 2 (OLSRv2)
Author(s): Thomas Clausen, Christopher Dearlove
This specification updates the Optimized Link State Routing Protocol version 2 (OLSRv2) with an optimization to improve the selection of routing MPRs. The optimization retains full interoperability between implementations of OLSRv2 with and without this optimization....
Mobile Ad hoc Networking (MANET) C. Dearlove Internet-Draft BAE Systems ATC Updates: OLSRv2 (if approved) T. Clausen Intended status: Standards Track LIX, Ecole Polytechnique Expires: January 13, 2014 July 12, 2013 Routing MPR Optimization for the Optimized Link State Routing Protocol version 2 (OLSRv2) draft-dearlove-manet-olsrv2-rmpr-optimization-00 Abstract This specification updates the Optimized Link State Routing Protocol version 2 (OLSRv2) with an optimization to improve the selection of routing MPRs. The optimization retains full interoperability between implementations of OLSRv2 with and without this optimization. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. 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 http://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 January 13, 2014. Copyright Notice Copyright (c) 2013 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 (http://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 Dearlove & Clausen Expires January 13, 2014 [Page 1] Internet-Draft OLSRv2 Routing MPR Optimization July 2013 described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Applicability Statement . . . . . . . . . . . . . . . . . . . . 3 4. Routing MPR Selection . . . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 8.1. Normative References . . . . . . . . . . . . . . . . . . . 5 8.2. Informative References . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 Dearlove & Clausen Expires January 13, 2014 [Page 2] Internet-Draft OLSRv2 Routing MPR Optimization July 2013 1. Introduction The Optimized Link State Routing Protocol, version 2 [OLSRv2] is a proactive link state routing protocol designed for use in mobile ad hoc networks (MANETs) [RFC2501]. This document improves one area of that specification. One improvement included in OLSRv2, compared to its predecessor described in [RFC3626], is the use of link metrics, rather than minimum hop routing. A rationale for how link metrics were included in OLSRv2 is documented in [RFC6966-to-be]. However, one aspect of the use of link metrics described in [RFC6966-to-be], the removal of some unnecessarily selected routing MPRs, was not included in [OLSRv2]. This specification updates OLSRv2 to include this optimization. Note that an implementation using this optimization is not strictly compliant with the current specification [OLSRv2], but is fully interoperable with implementations not using this optimization. This specification updates [OLSRv2] to specify that an implementation using this removal is compliant with the protocol OLSRv2. 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC 2119]. Additionally, this document uses the terminology of [OLSRv2]. 3. Applicability Statement This specification updates [OLSRv2]. As such it is applicable to all implementations of this protocol. The optimization presented in this specification is simply permissive, it allows an additional optimization, and there is no requirement for any implementation to include it. However inclusion of this optimization is advised, it can, in some cases, create smaller and fewer messages, without ever having the opposite effect. [OLSRv2] defines the properties for the selection of routing MPRs (multipoint relays) from among a router's symmetric 1-hop neighbors as properties that correspond first to that the selected MPRs consist of a set of symmetric 1-hop neighbors that cover all the symmetric 2-hop neighbors, and second that they do so retaining a minimum Dearlove & Clausen Expires January 13, 2014 [Page 3] Internet-Draft OLSRv2 Routing MPR Optimization July 2013 distance route (1-hop, if present, or 2-hop) to each symmetric 2-hop neighbor. The discussion in the latter part of Section 6.2 of [RFC6966-to-be] indicates that this requirement is over-prescriptive for routing MPR selection. The update to [OLSRv2] described in this specification permits a router to use the described optimization, while still being considered compliant. Note that, whether considered compliant or not, a router that implements the optimization, described in this specification, will interoperate successfully with routers not implementing this optimization. 4. Routing MPR Selection A set of routing MPRs created as specified in [OLSRv2] MAY be optimized in the following manner. Note that this uses the notation of Section 18.3 of [OLSRv2]: 1. If there is a sequence x_0, ..., x_n of elements of N1 such that: * x_0 is a routing MPR, * x_1, ... , x_n have corresponding elements y_1, ..., y_n of N2, and * d1(x_0) + d2(x_0,y_1) + ... + d2(x_m-1,y_m) < d1(x_m) for m = 1, ... , n, then x_1 to x_n may be removed from the set of routing MPRs, if selected. Note that "corresponding elements" in N1 and N2 means that these elements represent the same router. All of this information is available from information gathered by NHDP [RFC6130]. It is RECOMMENDED that all OLSRv2 routers use this optimization. 5. IANA Considerations This document has no actions for IANA. 6. Security Considerations The update to [OLSRv2] does not introduce any new protocol signals, compared to the already published specifications of the protocol, nor Dearlove & Clausen Expires January 13, 2014 [Page 4] Internet-Draft OLSRv2 Routing MPR Optimization July 2013 does it change the processing of any received protocol signals. This update to [OLSRv2] permits a compliant implementation of OLSRv2 to (potentially) eliminate some redundant information from the routing MPR sets otherwise generated by the algorithms described in [OLSRv2], and therefore also eliminate the need for including that information in generated TC messages. Because this information is not used when included, this update to [OLSRv2] does not present any additional security considerations, beyond those described in [OLSRv2]. 7. Acknowledgments The authors would like to gratefully acknowledge Philippe Jacquet (Alcatel-Lucent) for intense technical discussions and comments. 8. References 8.1. Normative References [OLSRv2] Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg, "The Optimized Link State Routing Protocol version 2", work in progress draft-ietf-manet-olsrv2-19, March 2013. [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC6130] Clausen, T., Dean, J., and C. Dearlove, "Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP)", RFC6130, April 2011. 8.2. Informative References [RFC2501] Macker, J. and S. Corson, "Mobile Ad hoc Networking (MANET): Routing Protocol Performance Issues and Evaluation Considerations", RFC2501, January 1999. [RFC3626] Clausen, T. and P. Jacquet, "The Optimized Link State Routing Protocol", RFC3626, October 2003. [RFC6966-to-be] Clausen, T., Dearlove, C., and P. Jacquet, "Rationale for the Use of Link Metrics in the Optimized Link State Routing Protocol Version 2 (OLSRv2)", RFC 6966, TBD 2013. Dearlove & Clausen Expires January 13, 2014 [Page 5] Internet-Draft OLSRv2 Routing MPR Optimization July 2013 Authors' Addresses Christopher Dearlove BAE Systems Advanced Technology Centre West Hanningfield Road Great Baddow, Chelmsford United Kingdom Phone: +44 1245 242194 Email: email@example.com URI: http://www.baesystems.com/ Thomas Heide Clausen LIX, Ecole Polytechnique Phone: +33 6 6058 9349 Email: T.Clausen@computer.org URI: http://www.ThomasClausen.org/ Dearlove & Clausen Expires January 13, 2014 [Page 6]