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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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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