Network Working Group L. Martini, Ed.
Request for Comments: 4447 E. Rosen
Category: Standards Track Cisco Systems, Inc.
N. El-Aawar
Level 3 Communications, LLC.
T. Smith
Network Appliance, Inc.
G. Heron
Tellabs
April 2006
Pseudowire Setup and Maintenance
Using the Label Distribution Protocol (LDP)
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
Layer 2 services (such as Frame Relay, Asynchronous Transfer Mode,
and Ethernet) can be "emulated" over an MPLS backbone by
encapsulating the Layer 2 Protocol Data Units (PDU) and transmitting
them over "pseudowires". It is also possible to use pseudowires to
provide low-rate Time Division Multiplexed and a Synchronous Optical
NETworking circuit emulation over an MPLS-enabled network. This
document specifies a protocol for establishing and maintaining the
pseudowires, using extensions to Label Distribution Protocol (LDP).
Procedures for encapsulating Layer 2 PDUs are specified in a set of
companion documents.
Martini, et al. Standards Track [Page 1]
RFC 4447 PWE3 Using LDP April 2006
Table of Contents
1. Introduction ....................................................3
2. Specification of Requirements ...................................5
3. The Pseudowire Label ............................................5
4. Details Specific to Particular Emulated Services ................7
4.1. IP Layer 2 Transport .......................................7
5. LDP .............................................................7
5.1. LDP Extensions .............................................8
5.2. The PWid FEC Element .......................................8
5.3. The Generalized PWid FEC Element ..........................10
5.3.1. Attachment Identifiers .............................11
5.3.2. Encoding the Generalized ID FEC Element ............13
5.3.2.1. Interface Parameters TLV ..................14
5.3.2.2. PW Grouping TLV ...........................14
5.3.3. Signaling Procedures ...............................15
5.4. Signaling of Pseudowire Status ............................16
5.4.1. Use of Label Mappings Messages .....................16
5.4.2. Signaling PW Status ................................17
5.4.3. Pseudowire Status Negotiation Procedures ...........18
5.5. Interface Parameters Sub-TLV ..............................19
6. Control Word ...................................................20
6.1. PW Types for Which the Control Word is REQUIRED ...........20
6.2. PW Types for Which the Control Word is NOT Mandatory ......21
6.3. LDP Label Withdrawal Procedures ...........................22
6.4. Sequencing Considerations .................................23
6.4.1. Label Advertisements ...............................23
6.4.2. Label Release ......................................24
7. IANA Considerations ............................................24
7.1. LDP TLV TYPE ..............................................24
7.2. LDP Status Codes ..........................................24
7.3. FEC Type Name Space .......................................25
8. Security Considerations ........................................25
8.1. Data-Plane Security .......................................25
8.2. Control-Plane Security ....................................26
9. Acknowledgements ...............................................27
10. Normative References ..........................................27
11. Informative References ........................................27
12. Additional Contributing Authors ...............................28
Appendix A. C-bit Handling Procedures Diagram .....................31
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