BGP-Based Auto-Discovery for Layer-1 VPNs
RFC 5195

 
Document Type RFC - Proposed Standard (June 2008; No errata)
Last updated 2013-03-02
Replaces draft-ouldbrahim-l1vpn-bgp-auto-discovery
Stream IETF
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IESG IESG state RFC 5195 (Proposed Standard)
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Responsible AD David Ward
Send notices to l1vpn-chairs@ietf.org, draft-ietf-l1vpn-bgp-auto-discovery@ietf.org
Network Working Group                                     H. Ould-Brahim
Request for Comments: 5195                                      D. Fedyk
Category: Standards Track                                         Nortel
                                                              Y. Rekhter
                                                        Juniper Networks
                                                               June 2008

               BGP-Based Auto-Discovery for Layer-1 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.

Abstract

   The purpose of this document is to define a BGP-based auto-discovery
   mechanism for Layer-1 VPNs (L1VPNs).  The auto-discovery mechanism
   for L1VPNs allows the provider network devices to dynamically
   discover the set of Provider Edges (PEs) having ports attached to
   Customer Edge (CE) members of the same VPN.  That information is
   necessary for completing the signaling phase of L1VPN connections.
   One main objective of a L1VPN auto-discovery mechanism is to support
   the "single-end provisioning" model, where addition of a new port to
   a given L1VPN would involve configuration changes only on the PE that
   has this port and on the CE that is connected to the PE via this
   port.

1.  Introduction

   The purpose of this document is to define a BGP-based auto-discovery
   mechanism for Layer-1 VPNs (L1VPNs) [L1VPN-FRMK].  The auto-discovery
   mechanism for L1VPNs allows the provider network devices to
   dynamically discover the set of PEs having ports attached to CE
   members of the same VPN.  That information is necessary for
   completing the signaling phase of L1VPN connections.  One main
   objective of a L1VPN auto-discovery mechanism is to support the
   "single-end provisioning" model, where addition of a new port to a
   given L1VPN would involve configuration changes only on the PE that
   has this port and on the CE that is connected to the PE via this
   port.

Ould-Brahim, et al.         Standards Track                     [Page 1]
RFC 5195             BGP Auto-Discovery for L1VPNs             June 2008

   The auto-discovery mechanism proceeds by having a PE advertise to
   other PEs the following information, at a minimum: its own IP address
   and the list of <private address, provider address> tuples local to
   that PE.  Once that information is received, the remote PEs will
   identify the list of VPN members they have in common with the
   advertising PE, and use the information carried within the discovery
   mechanism to perform address resolution during the signaling phase of
   Layer-1 VPN connections.

   Figure 1 highlights the network reference for using a BGP-based
   auto-discovery mechanism for Layer-1 VPNs.  For the purpose of the
   auto-discovery mechanism, BGP is running only on the provider
   network.  The PEs maintain per-VPN information tables called Port
   Information Tables (PITs) related to <private address, provider
   address> information.  More information on the PITs is in Section 2.

                   PE1                        PE2
               +---------+             +--------------+
   +--------+  | +------+|             | +----------+ | +--------+
   |  VPN-A |  | |VPN-A ||             | |  VPN-A   | | |  VPN-A |
   |   CE1  |--| |PIT   ||  BGP route  | |  PIT     | |-|   CE2  |
   +--------+  | |      ||<----------->| |          | | +--------+
               | +------+| Distribution| +----------+ |
               |         |             |              |
   +--------+  | +------+|             | +----------+ | +--------+
   | VPN-B  |  | |VPN-B ||  --------   | |   VPN-B  | | |  VPN-B |
   |  CE1   |--| |PIT   ||-(   GMPLS )-| |   PIT    | |-|   CE2  |
   +--------+  | |      || (Backbone ) | |          | | +--------+
               | +------+|  ---------  | +----------+ |
               |         |             |              |
   +--------+  | +-----+ |             | +----------+ | +--------+
   | VPN-C  |  | |VPN-C| |             | |   VPN-C  | | |  VPN-C |
   |  CE1   |--| |PIT  | |             | |   PIT    | |-|   CE2  |
   +--------+  | |     | |             | |          | | +--------+
               | +-----+ |             | +----------+ |
               +---------+             +--------------+

                   Figure 1: BGP Auto-Discovery for L1VPN

   [L1VPN-FRMK] describes two modes of operation for a L1VPN: the basic
   mode and the enhanced mode.  This document describes an auto-
   discovery mechanism for the basic mode only.
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