Internet DRAFT - draft-ietf-manet-olsrv2-rmpr-optimization

draft-ietf-manet-olsrv2-rmpr-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: August 25, 2014                               February 21, 2014


 Routing MPR Optimization for the Optimized Link State Routing Protocol
                           version 2 (OLSRv2)
              draft-ietf-manet-olsrv2-rmpr-optimization-01

Abstract

   This specification updates the Optimized Link State Routing Protocol
   version 2 (OLSRv2) with an optimization to improve the selection of
   routing Multi-Point Relays.  The optimization retains full
   interoperability between implementations of OLSRv2 with and without
   this optimization.

Status of this Memo

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   This Internet-Draft will expire on August 25, 2014.

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   the Trust Legal Provisions and are provided without warranty as
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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  . . . . . . . . . . . . . . . . . . . . . . . . 5


































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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 Multi-Point Relays (MPRs), was
   not included in [OLSRv2].  This specification updates OLSRv2 to
   include this optimization.

   Note that this optimization does not impact interoperability:
   implementations which do, and which do not, implement this
   optimization will interoperate seamlessly.


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
   [RFC2119].

   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
   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



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   [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 18.2 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].


5.  IANA Considerations

   This document has no actions for IANA.

   [This section may be removed by the RFC Editor.]


6.  Security Considerations

   The update to [OLSRv2] does not introduce any new protocol signals,
   compared to the already published specifications of the protocol, nor
   does it change the processing of any received protocol signals.




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   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.

   [RFC2119]  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)",
              RFC 6130, April 2011.

8.2.  Informative References

   [RFC2501]  Macker, J. and S. Corson, "Mobile Ad hoc Networking
              (MANET): Routing Protocol Performance Issues and
              Evaluation Considerations", RFC 2501, January 1999.

   [RFC3626]  Clausen, T. and P. Jacquet, "The Optimized Link State
              Routing Protocol", RFC 3626, 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.







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Authors' Addresses

   Christopher Dearlove
   BAE Systems Advanced Technology Centre
   West Hanningfield Road
   Great Baddow, Chelmsford
   United Kingdom

   Phone: +44 1245 242194
   Email: chris.dearlove@baesystems.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/
































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