Pseudo Wire Emulation Edge-to-Edge (PWE3) Architecture
RFC 3985

Network Working Group                                     S. Bryant, Ed.
Request for Comments: 3985                                 Cisco Systems
Category: Informational                                     P. Pate, Ed.
                                                 Overture Networks, Inc.
                                                              March 2005

         Pseudo Wire Emulation Edge-to-Edge (PWE3) Architecture

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 (2005).

Abstract

   This document describes an architecture for Pseudo Wire Emulation
   Edge-to-Edge (PWE3).  It discusses the emulation of services such as
   Frame Relay, ATM, Ethernet, TDM, and SONET/SDH over packet switched
   networks (PSNs) using IP or MPLS.  It presents the architectural
   framework for pseudo wires (PWs), defines terminology, and specifies
   the various protocol elements and their functions.

Table of Contents

   1.   Introduction. . . . . . . . . . . . . . . . . . . . . . . . .  2
        1.1.  Pseudo Wire Definition. . . . . . . . . . . . . . . . .  2
        1.2.  PW Service Functionality. . . . . . . . . . . . . . . .  3
        1.3.  Non-Goals of This Document. . . . . . . . . . . . . . .  4
        1.4.  Terminology . . . . . . . . . . . . . . . . . . . . . .  4
   2.   PWE3 Applicability. . . . . . . . . . . . . . . . . . . . . .  6
   3.   Protocol Layering Model . . . . . . . . . . . . . . . . . . .  6
        3.1.  Protocol Layers . . . . . . . . . . . . . . . . . . . .  7
        3.2.  Domain of PWE3. . . . . . . . . . . . . . . . . . . . .  8
        3.3.  Payload Types . . . . . . . . . . . . . . . . . . . . .  8
   4.   Architecture of Pseudo Wires. . . . . . . . . . . . . . . . . 11
        4.1.  Network Reference Model . . . . . . . . . . . . . . . . 12
        4.2.  PWE3 Pre-processing . . . . . . . . . . . . . . . . . . 12
        4.3.  Maintenance Reference Model . . . . . . . . . . . . . . 16
        4.4.  Protocol Stack Reference Model. . . . . . . . . . . . . 17
        4.5.  Pre-processing Extension to Protocol Stack Reference
              Model . . . . . . . . . . . . . . . . . . . . . . . . . 17
   5.   PW Encapsulation. . . . . . . . . . . . . . . . . . . . . . . 18

Bryant & Pate               Standards Track                     [Page 1]
RFC 3985                   PWE3 Architecture                  March 2005

        5.1.  Payload Convergence Layer . . . . . . . . . . . . . . . 19
        5.2.  Payload-independent PW Encapsulation Layers . . . . . . 21
        5.3.  Fragmentation . . . . . . . . . . . . . . . . . . . . . 24
        5.4.  Instantiation of the Protocol Layers. . . . . . . . . . 24
   6.   PW Demultiplexer Layer and PSN Requirements . . . . . . . . . 27
        6.1.  Multiplexing. . . . . . . . . . . . . . . . . . . . . . 27
        6.2.  Fragmentation . . . . . . . . . . . . . . . . . . . . . 28
        6.3.  Length and Delivery . . . . . . . . . . . . . . . . . . 28
        6.4.  PW-PDU Validation . . . . . . . . . . . . . . . . . . . 28
        6.5.  Congestion Considerations . . . . . . . . . . . . . . . 28
   7.   Control Plane . . . . . . . . . . . . . . . . . . . . . . . . 29
        7.1.  Set-up or Teardown of Pseudo Wires. . . . . . . . . . . 29
        7.2.  Status Monitoring . . . . . . . . . . . . . . . . . . . 30
        7.3.  Notification of Pseudo Wire Status Changes. . . . . . . 30
        7.4.  Keep-alive. . . . . . . . . . . . . . . . . . . . . . . 31
        7.5.  Handling Control Messages of the Native Services. . . . 32
   8.   Management and Monitoring . . . . . . . . . . . . . . . . . . 32
        8.1.  Status and Statistics . . . . . . . . . . . . . . . . . 32
        8.2.  PW SNMP MIB Architecture. . . . . . . . . . . . . . . . 33
        8.3.  Connection Verification and Traceroute. . . . . . . . . 36
   9.   IANA Considerations . . . . . . . . . . . . . . . . . . . . . 37
   10.  Security Considerations . . . . . . . . . . . . . . . . . . . 37
   11.  Acknowledgements. . . . . . . . . . . . . . . . . . . . . . . 38
   12.  References. . . . . . . . . . . . . . . . . . . . . . . . . . 38
        12.1.  Normative References . . . . . . . . . . . . . . . . . 38
        12.2.  Informative References . . . . . . . . . . . . . . . . 39
   13.  Co-Authors. . . . . . . . . . . . . . . . . . . . . . . . . . 40
   14.  Editors' Addresses. . . . . . . . . . . . . . . . . . . . . . 41
        Full Copyright Statement. . . . . . . . . . . . . . . . . . . 42

1.  Introduction

   This document describes an architecture for Pseudo Wire Emulation
   Edge-to-Edge (PWE3) in support of [RFC3916].  It discusses the