A Framework for IP Based Virtual Private Networks
RFC 2764

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• 03

Network Working Group                                         B. Gleeson
Request for Comments: 2764                                        A. Lin
Category: Informational                                  Nortel Networks
                                                             J. Heinanen
                                                           Telia Finland
                                                             G. Armitage
                                                                A. Malis
                                                     Lucent Technologies
                                                           February 2000

           A Framework for IP Based Virtual Private Networks

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 (2000).  All Rights Reserved.

IESG Note

   This document is not the product of an IETF Working Group.  The IETF
   currently has no effort underway to standardize a specific VPN
   framework.

Abstract

   This document describes a framework for Virtual Private Networks
   (VPNs) running across IP backbones.  It discusses the various
   different types of VPNs, their respective requirements, and proposes
   specific mechanisms that could be used to implement each type of VPN
   using existing or proposed specifications.  The objective of this
   document is to serve as a framework for related protocol development
   in order to develop the full set of specifications required for
   widespread deployment of interoperable VPN solutions.

Gleeson, et al.              Informational                      [Page 1]
RFC 2764           IP Based Virtual Private Networks       February 2000

Table of Contents

   1.0 Introduction ................................................  4
   2.0 VPN Application and Implementation Requirements .............  5
   2.1 General VPN Requirements ....................................  5
   2.1.1 Opaque Packet Transport:  .................................  6
   2.1.2 Data Security .............................................  7
   2.1.3 Quality of Service Guarantees .............................  7
   2.1.4 Tunneling Mechanism .......................................  8
   2.2 CPE and Network Based VPNs ..................................  8
   2.3 VPNs and Extranets ..........................................  9
   3.0 VPN Tunneling ............................................... 10
   3.1 Tunneling Protocol Requirements for VPNs .................... 11
   3.1.1 Multiplexing .............................................. 11
   3.1.2 Signalling Protocol ....................................... 12
   3.1.3 Data Security ............................................. 13
   3.1.4 Multiprotocol Transport ................................... 14
   3.1.5 Frame Sequencing .......................................... 14
   3.1.6 Tunnel Maintenance ........................................ 15
   3.1.7 Large MTUs ................................................ 16
   3.1.8 Minimization of Tunnel Overhead ........................... 16
   3.1.9 Flow and congestion control ............................... 17
   3.1.10 QoS / Traffic Management ................................. 17
   3.2 Recommendations ............................................. 18
   4.0 VPN Types:  Virtual Leased Lines ............................ 18
   5.0 VPN Types:  Virtual Private Routed Networks ................. 20
   5.1 VPRN Characteristics ........................................ 20
   5.1.1 Topology .................................................. 23
   5.1.2 Addressing ................................................ 24
   5.1.3 Forwarding ................................................ 24
   5.1.4 Multiple concurrent VPRN connectivity ..................... 24
   5.2 VPRN Related Work ........................................... 24
   5.3 VPRN Generic Requirements ................................... 25
   5.3.1 VPN Identifier ............................................ 26
   5.3.2 VPN Membership Information Configuration .................. 27
   5.3.2.1 Directory Lookup ........................................ 27
   5.3.2.2 Explicit Management Configuration ....................... 28
   5.3.2.3 Piggybacking in Routing Protocols ....................... 28
   5.3.3 Stub Link Reachability Information ........................ 30
   5.3.3.1 Stub Link Connectivity Scenarios ........................ 30
   5.3.3.1.1 Dual VPRN and Internet Connectivity ................... 30
   5.3.3.1.2 VPRN Connectivity Only ................................ 30
   5.3.3.1.3 Multihomed Connectivity ............................... 31
   5.3.3.1.4 Backdoor Links ........................................ 31
   5.3.3.1 Routing Protocol Instance ............................... 31
   5.3.3.2 Configuration ........................................... 33