BGP/MPLS IP Virtual Private Networks (VPNs)
RFC 4364

Network Working Group                                           E. Rosen
Request for Comments: 4364                           Cisco Systems, Inc.
Obsoletes: 2547                                               Y. Rekhter
Category: Standards Track                         Juniper Networks, Inc.
                                                           February 2006

              BGP/MPLS 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 Internet Society (2006).

Abstract

   This document describes a method by which a Service Provider may use
   an IP backbone to provide IP Virtual Private Networks (VPNs) for its
   customers.  This method uses a "peer model", in which the customers'
   edge routers (CE routers) send their routes to the Service Provider's
   edge routers (PE routers); there is no "overlay" visible to the
   customer's routing algorithm, and CE routers at different sites do
   not peer with each other.  Data packets are tunneled through the
   backbone, so that the core routers do not need to know the VPN
   routes.

   This document obsoletes RFC 2547.

Rosen & Rekhter             Standards Track                     [Page 1]
RFC 4364                    BGP/MPLS IP VPNs               February 2006

Table of Contents

   1. Introduction ....................................................3
      1.1. Virtual Private Networks ...................................4
      1.2. Customer Edge and Provider Edge ............................5
      1.3. VPNs with Overlapping Address Spaces .......................6
      1.4. VPNs with Different Routes to the Same System ..............7
      1.5. SP Backbone Routers ........................................7
      1.6. Security ...................................................8
   2. Sites and CEs ...................................................8
   3. VRFs: Multiple Forwarding Tables in PEs .........................9
      3.1. VRFs and Attachment Circuits ...............................9
      3.2. Associating IP Packets with VRFs ..........................10
      3.3. Populating the VRFs .......................................11
   4. VPN Route Distribution via BGP .................................12
      4.1. The VPN-IPv4 Address Family ...............................13
      4.2. Encoding of Route Distinguishers ..........................14
      4.3. Controlling Route Distribution ............................15
           4.3.1. The Route Target Attribute .........................15
           4.3.2. Route Distribution Among PEs by BGP ................17
           4.3.3. Use of Route Reflectors ............................20
           4.3.4. How VPN-IPv4 NLRI Is Carried in BGP ................22
           4.3.5. Building VPNs Using Route Targets ..................23
           4.3.6. Route Distribution Among VRFs in a Single PE .......23
   5. Forwarding .....................................................23
   6. Maintaining Proper Isolation of VPNs ...........................26
   7. How PEs Learn Routes from CEs ..................................27
   8. How CEs Learn Routes from PEs ..................................30
   9. Carriers' Carriers .............................................30
   10. Multi-AS Backbones ............................................32
   11. Accessing the Internet from a VPN .............................34
   12. Management VPNs ...............................................36
   13. Security Considerations .......................................37
      13.1. Data Plane ...............................................37
      13.2. Control Plane ............................................39
      13.3. Security of P and PE Devices .............................39
   14. Quality of Service ............................................39
   15. Scalability ...................................................40
   16. IANA Considerations ...........................................40
   17. Acknowledgements ..............................................41
   18. Contributors ..................................................41
   19. Normative References ..........................................44
   20. Informative References ........................................45

Rosen & Rekhter             Standards Track                     [Page 2]
RFC 4364                    BGP/MPLS IP VPNs               February 2006