Internet Engineering Task Force (IETF) P. Marques
Request for Comments: 6368
Category: Standards Track R. Raszuk
ISSN: 2070-1721 NTT MCL
K. Patel
Cisco Systems
K. Kumaki
T. Yamagata
KDDI Corporation
September 2011
Internal BGP as the Provider/Customer Edge Protocol for
BGP/MPLS IP Virtual Private Networks (VPNs)
Abstract
This document defines protocol extensions and procedures for BGP
Provider/Customer Edge router iteration in BGP/MPLS IP VPNs. These
extensions and procedures have the objective of making the usage of
the BGP/MPLS IP VPN transparent to the customer network, as far as
routing information is concerned.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6368.
Marques, et al. Standards Track [Page 1]
RFC 6368 Internal BGP as PE/CE Protocol September 2011
Copyright Notice
Copyright (c) 2011 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
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction ....................................................2
2. Requirements Language ...........................................3
3. IP VPN as a Route Server ........................................3
4. Path Attributes .................................................5
5. BGP Customer Route Attributes ...................................6
6. Next-Hop Handling ...............................................7
7. Exchanging Routes between Different VPN Customer Networks .......8
8. Deployment Considerations ......................................10
9. Security Considerations ........................................12
10. IANA Considerations ...........................................12
11. Acknowledgments ...............................................12
12. References ....................................................13
12.1. Normative References .....................................13
12.2. Informative References ...................................13
1. Introduction
In current deployments, when BGP is used as the Provider/Customer
Edge routing protocol, these peering sessions are typically
configured as an external peering between the VPN provider autonomous
system (AS) and the customer network autonomous system. At each
External BGP boundary, BGP path attributes [RFC4271] are modified as
per standard BGP rules. This includes prepending the AS_PATH
attribute with the autonomous-system number of the originating
Customer Edge (CE) router and the autonomous-system number(s) of the
Provider Edge (PE) router(s).
Marques, et al. Standards Track [Page 2]
RFC 6368 Internal BGP as PE/CE Protocol September 2011
In order for such routes not to be rejected by AS_PATH loop
detection, a PE router advertising a route received from a remote PE
often remaps the customer network autonomous-system number to its
own. Otherwise, the customer network can use different autonomous-
system numbers at different sites or configure their CE routers to
accept routes containing their own AS number.
While this technique works well in situations where there are no BGP
datatracker.ietf.org