Inter-Domain Routing P. Jakma Internet-Draft July 28, 2009 Expires: January 29, 2010 Revisions to the BGP 'Minimum Route Advertisement Interval' draft-ietf-idr-mrai-dep-01 Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on January 29, 2010. Copyright Notice Copyright (c) 2009 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 in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. 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. Jakma Expires January 29, 2010 [Page 1] Internet-Draft BGP MRAI Timer Revision July 2009 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 Jakma Expires January 29, 2010 [Page 2] Internet-Draft BGP MRAI Timer Revision July 2009 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 [BGP]. This timer acts to rate-limit updates, on a per- destination basis. [BGP] 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 [BGP] 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 [BGP] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006. Jakma Expires January 29, 2010 [Page 3] Internet-Draft BGP MRAI Timer Revision July 2009 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, BCP 14, February 2001. Author's Address Paul Jakma 2/1, 5 Moir St. Glasgow G1 5AE Scotland Email: paul@jakma.org Jakma Expires January 29, 2010 [Page 4]