draft-ietf-idr-bgp-bestpath-selection-criteria-05.txt   draft-ietf-idr-bgp-bestpath-selection-criteria-06.txt 
IDR Working Group Rajiv Asati IDR Working Group Rajiv Asati
Internet Draft Cisco Systems Internet Draft Cisco Systems
Intended status: Standards Track Intended status: Standards Track
Expires: February 23, 2012 Expires: August 25, 2013
August 23, 2011 February 25, 2013
BGP Bestpath Selection Criteria Enhancement BGP Bestpath Selection Criteria Enhancement
draft-ietf-idr-bgp-bestpath-selection-criteria-05.txt draft-ietf-idr-bgp-bestpath-selection-criteria-06.txt
Abstract Abstract
BGP specification [RFC4271] prescribes 'BGP next-hop reachability' BGP specification [RFC4271] prescribes 'BGP next-hop reachability'
as one of the key 'Route Resolvability Condition' that must be as one of the key 'Route Resolvability Condition' that must be
satisfied before the BGP bestpath candidate selection. This satisfied before the BGP bestpath candidate selection. This
condition, however, may not be sufficient (as explained in the condition, however, may not be sufficient (as explained in the
Appendix section) and desire further granularity. Appendix section) and desire further granularity.
This document defines enhances the "Route Resolvability Condition" This document defines enhances the "Route Resolvability Condition"
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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months and may be updated, replaced, or obsoleted by other documents months and may be updated, replaced, or obsoleted by other documents
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reference material or to cite them other than as "work in progress." reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 23, 2012. This Internet-Draft will expire on August 25, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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document must include Simplified BSD License text as described in document must include Simplified BSD License text as described in
Section 4.e of the Trust Legal Provisions and are provided without Section 4.e of the Trust Legal Provisions and are provided without
warranty as described in the Simplified BSD License. warranty as described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction...................................................2 1. Introduction...................................................2
2. Specification Language.........................................3 2. Specification Language.........................................3
3. Route Resolvability Condition - Modification...................3 3. Route Resolvability Condition - Modification...................3
4. Conclusions....................................................4 4. Conclusions....................................................4
5. Security Considerations........................................5 5. Security Considerations........................................4
6. IANA Considerations............................................5 6. IANA Considerations............................................5
7. Acknowledgments................................................5 7. Acknowledgments................................................5
8. Appendix.......................................................5 8. Appendix.......................................................5
9. References.....................................................8 9. References.....................................................7
Author's Addresses................................................9 Author's Addresses................................................8
1. Introduction 1. Introduction
As per BGP specification [RFC4271], when a router receives a BGP As per BGP specification [RFC4271], when a router receives a BGP
path, BGP must qualify it as the valid candidate prior to the BGP path, BGP must qualify it as the valid candidate prior to the BGP
bestpath selection using the 'Route Resolvability Condition' bestpath selection using the 'Route Resolvability Condition'
(section#9.1.2.1 of RFC4271]. After the path gets qualified as the (section#9.1.2.1 of RFC4271]. After the path gets qualified as the
bestpath candidate, it becomes eligible to be the bestpath, and may bestpath candidate, it becomes eligible to be the bestpath, and may
get advertised out to the neigbhor(s), if it became the bestpath. get advertised out to the neigbhor(s), if it became the bestpath.
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None. None.
7. Acknowledgments 7. Acknowledgments
Yakov Rekhter provided critical suggestions and feedback to improve Yakov Rekhter provided critical suggestions and feedback to improve
this document. Thanks to John Scudder and Chandrashekhar Appanna for this document. Thanks to John Scudder and Chandrashekhar Appanna for
contributing to the discussions that formed the basis of this contributing to the discussions that formed the basis of this
document. Thanks to Ilya Varlashkin and Michael Benjamin, who made document. Thanks to Ilya Varlashkin and Michael Benjamin, who made
the case to revive this document and provided useful feedback. Also the case to revive this document and provided useful feedback. Also
thanks to Keyur Patel, Robert Raszuk and Samita Chakrabarti. thanks to Keyur Patel for his feedback.
This document was prepared using 2-Word-v2.0.template.dot. This document was prepared using 2-Word-v2.0.template.dot.
8. Appendix 8. Appendix
8.1. Problem Applicability 8.1. Problem Applicability
In IP networks using BGP, a router would continue to attract traffic In IP networks using BGP, a router would continue to attract traffic
by advertising the BGP prefix reachability to neighbor(s) as long as by advertising the BGP prefix reachability to neighbor(s) as long as
the router had a route to the next-hop in its routing table, but the router had a route to the next-hop in its routing table, but
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