Constrained Route Distribution for Border Gateway Protocol/MultiProtocol Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual Private Networks (VPNs)
RFC 4684
Document | Type |
RFC - Proposed Standard
(November 2006; Errata)
Updates RFC 4364
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Authors | Pedro Marques , Luyuan Fang , Jim Guichard , Luca Martini , Robert Raszuk , Keyur Patel , Ron Bonica | ||
Last updated | 2020-01-21 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized with errata bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 4684 (Proposed Standard) | |
Action Holders |
(None)
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Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Mark Townsley | ||
Send notices to | rcallon@juniper.net, rick@rhwilder.net |
Network Working Group P. Marques Request for Comments: 4684 R. Bonica Updates: 4364 Juniper Networks Category: Standards Track L. Fang L. Martini R. Raszuk K. Patel J. Guichard Cisco Systems, Inc. November 2006 Constrained Route Distribution for Border Gateway Protocol/MultiProtocol Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual Private Networks (VPNs) Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The IETF Trust (2006). Abstract This document defines Multi-Protocol BGP (MP-BGP) procedures that allow BGP speakers to exchange Route Target reachability information. This information can be used to build a route distribution graph in order to limit the propagation of Virtual Private Network (VPN) Network Layer Reachability Information (NLRI) between different autonomous systems or distinct clusters of the same autonomous system. This document updates RFC 4364. Marques, et al. Standards Track [Page 1] RFC 4684 Route Target (RT) Constrain November 2006 Table of Contents 1. Introduction ....................................................2 1.1. Terminology ................................................3 2. Specification of Requirements ...................................4 3. NLRI Distribution ...............................................4 3.1. Inter-AS VPN Route Distribution ............................4 3.2. Intra-AS VPN Route Distribution ............................6 4. Route Target Membership NLRI Advertisements .....................8 5. Capability Advertisement ........................................9 6. Operation .......................................................9 7. Deployment Considerations ......................................10 8. Security Considerations ........................................11 9. Acknowledgements ...............................................11 10. References ....................................................11 10.1. Normative References .....................................11 10.2. Informative References ...................................12 1. Introduction In BGP/MPLS IP VPNs, PE routers use Route Target (RT) extended communities to control the distribution of routes into VRFs. Within a given iBGP mesh, PE routers need only hold routes marked with Route Targets pertaining to VRFs that have local CE attachments. It is common, however, for an autonomous system to use route reflection [2] in order to simplify the process of bringing up a new PE router in the network and to limit the size of the iBGP peering mesh. In such a scenario, as well as when VPNs may have members in more than one autonomous system, the number of routes carried by the inter-cluster or inter-as distribution routers is an important consideration. In order to limit the VPN routing information that is maintained at a given route reflector, RFC 4364 [3] suggests, in Section 4.3.3, the use of "Cooperative Route Filtering" [7] between route reflectors. This document extends the RFC 4364 [3] Outbound Route Filtering (ORF) work to include support for multiple autonomous systems and asymmetric VPN topologies such as hub-and-spoke. Although it would be possible to extend the encoding currently defined for the extended-community ORF in order to achieve this purpose, BGP itself already has all the necessary machinery for dissemination of arbitrary information in a loop-free fashion, both within a single autonomous system, as well as across multiple autonomous systems. Marques, et al. Standards Track [Page 2] RFC 4684 Route Target (RT) Constrain November 2006 This document builds on the model described in RFC 4364 [3] and on the concept of cooperative route filtering by adding the ability to propagate Route Target membership information between iBGP meshes. It is designed to supersede "cooperative route filtering" for VPNShow full document text