An Architecture for Multi-Segment Pseudowire Emulation Edge-to-Edge
RFC 5659

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Network Working Group                                           M. Bocci
Request for Comments: 5659                                Alcatel-Lucent
Category: Informational                                        S. Bryant
                                                           Cisco Systems
                                                            October 2009

 An Architecture for Multi-Segment Pseudowire Emulation Edge-to-Edge

Abstract

   This document describes an architecture for extending pseudowire
   emulation across multiple packet switched network (PSN) segments.
   Scenarios are discussed where each segment of a given edge-to-edge
   emulated service spans a different provider's PSN, as are other
   scenarios where the emulated service originates and terminates on the
   same provider's PSN, but may pass through several PSN tunnel segments
   in that PSN.  It presents an architectural framework for such multi-
   segment pseudowires, defines terminology, and specifies the various
   protocol elements and their functions.

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 and License Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   include Simplified BSD License text as described in Section 4.e of
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   described in the BSD License.

Bocci & Bryant               Informational                      [Page 1]
RFC 5659            Multi-Segment PWE3 Architecture         October 2009

Table of Contents

   1. Introduction ....................................................3
      1.1. Motivation and Context .....................................3
      1.2. Non-Goals of This Document .................................6
      1.3. Terminology ................................................6
   2. Applicability ...................................................8
   3. Protocol Layering Model .........................................8
      3.1. Domain of MS-PW Solutions ..................................9
      3.2. Payload Types ..............................................9
   4. Multi-Segment Pseudowire Reference Model ........................9
      4.1. Intra-Provider Connectivity Architecture ..................11
           4.1.1. Intra-Provider Switching Using ACs .................11
           4.1.2. Intra-Provider Switching Using PWs .................11
      4.2. Inter-Provider Connectivity Architecture ..................11
           4.2.1. Inter-Provider Switching Using ACs .................12
           4.2.2. Inter-Provider Switching Using PWs .................12
   5. PE Reference Model .............................................13
      5.1. Pseudowire Pre-Processing .................................13
           5.1.1. Forwarding .........................................13
           5.1.2. Native Service Processing ..........................14
   6. Protocol Stack Reference Model .................................14
   7. Maintenance Reference Model ....................................15
   8. PW Demultiplexer Layer and PSN Requirements ....................16
      8.1. Multiplexing ..............................................16
      8.2. Fragmentation .............................................17
   9. Control Plane ..................................................17
      9.1. Setup and Placement of MS-PWs .............................17
      9.2. Pseudowire Up/Down Notification ...........................18
      9.3. Misconnection and Payload Type Mismatch ...................18
   10. Management and Monitoring .....................................18
   11. Congestion Considerations .....................................19
   12. Security Considerations .......................................20
   13. Acknowledgments ...............................................23
   14. References ....................................................23
      14.1. Normative References .....................................23
      14.2. Informative References ...................................23

Bocci & Bryant               Informational                      [Page 2]
RFC 5659            Multi-Segment PWE3 Architecture         October 2009

1.  Introduction

   RFC 3985 [1] defines the architecture for pseudowires, where a
   pseudowire (PW) both originates and terminates on the edge of the
   same packet switched network (PSN).  The PW label is unchanged