RFC 2547 (rfc2547) - Page 1 of 25
BGP/MPLS VPNs
Alternative Format: Original Text Document
Network Working Group E. Rosen
Request for Comments: 2547 Y. Rekhter
Category: Informational Cisco Systems, Inc.
March 1999
BGP/MPLS VPNs
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1999). All Rights Reserved.
Abstract
This document describes a method by which a Service Provider with an
IP backbone may provide VPNs (Virtual Private Networks) for its
customers. MPLS (Multiprotocol Label Switching) is used for
forwarding packets over the backbone, and BGP (Border Gateway
Protocol) is used for distributing routes over the backbone. The
primary goal of this method is to support the outsourcing of IP
backbone services for enterprise networks. It does so in a manner
which is simple for the enterprise, while still scalable and flexible
for the Service Provider, and while allowing the Service Provider to
add value. These techniques can also be used to provide a VPN which
itself provides IP service to customers.
Table of Contents
1 Introduction ....................................... 2
1.1 Virtual Private Networks ........................... 2
1.2 Edge Devices ....................................... 3
1.3 VPNs with Overlapping Address Spaces ............... 4
1.4 VPNs with Different Routes to the Same System ...... 4
1.5 Multiple Forwarding Tables in PEs .................. 5
1.6 SP Backbone Routers ................................ 5
1.7 Security ........................................... 5
2 Sites and CEs ...................................... 6
3 Per-Site Forwarding Tables in the PEs .............. 6
3.1 Virtual Sites ...................................... 8
4 VPN Route Distribution via BGP ..................... 8
4.1 The VPN-IPv4 Address Family ........................ 9
4.2 Controlling Route Distribution ..................... 10
Rosen & Rekhter Informational