Inter-Domain Routing                                            P. Jakma
Internet-Draft                                      DCS, Uni. of Glasgow
Updates: rfc4271                                        October 12, 2010
(if approved)
Intended status: Standards Track
Expires: April 15, 2011


      Revisions to the BGP 'Minimum Route Advertisement Interval'
                       draft-ietf-idr-mrai-dep-03

Abstract

   This document revises the specification of the BGP MRAI timer, by
   deprecating the previously recommended values and by allowing for
   withdrawals to be exempted from the MRAI.

Status of this Memo

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   This Internet-Draft will expire on April 15, 2011.

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Table of Contents

   1.  Requirements Language . . . . . . . . . . . . . . . . . . . . . 3
   2.  Background  . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Revision  . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 3
   6.  Normative References  . . . . . . . . . . . . . . . . . . . . . 3
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 4










































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1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].


2.  Background

   The Minimum Route Advertisement Interval (MRAI) timer is specified in
   [RFC4271].  This timer acts to rate-limit updates, on a per-
   destination basis.  [RFC4271] suggests values of 30s and 5s for this
   interval for eBGP and iBGP respectively.  The MRAI must also be
   applied to withdrawals according to RFC4271, a change from the
   earlier [RFC1771].

   The MRAI timer has a significant effect on the convergence of BGP, in
   terms of convergence time, the number of messages, amongst other
   metrics.  The optimum value for this timer is hard to estimate, never
   mind calculate and will differ between networks, and probably even
   different subsets of the same network.


3.  Revision

   The suggested default values for the
   MinRouteAdvertisementIntervalTimer given in [RFC4271] are deprecated.
   The appropriate choice of default values is left to the discretion of
   implementors.  Implementations SHOULD provide a means to allow
   operators to choose values appropriate to their requirements, on a
   per-peer and per-AFI/SAFI basis.  Implementations MAY exempt
   withdrawals from the MRAI timer.


4.  IANA Considerations

   There are no requests made to IANA in this document.


5.  Security Considerations

   This document raises no new security considerations.


6.  Normative References

   [RFC1771]  Rekhter, Y. and T. Li, "A Border Gateway Protocol 4
              (BGP-4)", RFC 1771, March 1995.



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   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4271]  Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
              Protocol 4 (BGP-4)", RFC 4271, January 2006.


Author's Address

   Paul Jakma
   School of Computing Science, Uni. of Glasgow
   Sir Alwyn Williams Building
   University of Glasgow
   Glasgow  G12 8QQ
   UK

   Email: paulj@dcs.gla.ac.uk


































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