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Encapsulation Methods for Transport of PPP/High-Level Data Link Control (HDLC) over MPLS Networks
RFC 4618

Document type: RFC - Proposed Standard (September 2006; No errata)
Document stream: IETF
Last updated: 2013-03-02
Other versions: plain text, pdf, html

IETF State: (None)
Consensus: Unknown
Document shepherd: No shepherd assigned

IESG State: RFC 4618 (Proposed Standard)
Responsible AD: Mark Townsley
Send notices to: pwe3-chairs@tools.ietf.org

Network Working Group                                         L. Martini
Request for Comments: 4618                                      E. Rosen
Category: Standards Track                            Cisco Systems, Inc.
                                                                G. Heron
                                                                A. Malis
                                                                 Tellabs
                                                          September 2006

                Encapsulation Methods for Transport of
       PPP/High-Level Data Link Control (HDLC) over MPLS Networks

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

   A pseudowire (PW) can be used to carry Point to Point Protocol (PPP)
   or High-Level Data Link Control (HDLC) Protocol Data Units over a
   Multiprotocol Label Switching (MPLS) network without terminating the
   PPP/HDLC protocol.  This enables service providers to offer
   "emulated" HDLC, or PPP link services over existing MPLS networks.
   This document specifies the encapsulation of PPP/HDLC Packet Data
   Units (PDUs) within a pseudowire.

Martini, et al.             Standards Track                     [Page 1]
RFC 4618            Transport of PPP/HDLC over MPLS       September 2006

Table of Contents

   1. Introduction ....................................................2
   2. Specification of Requirements ...................................2
   3. Applicability Statement .........................................5
   4. General Encapsulation Method ....................................6
      4.1. The Control Word ...........................................6
      4.2. MTU Requirements ...........................................8
   5. Protocol-Specific Details .......................................9
      5.1. HDLC .......................................................9
      5.2. Frame Relay Port Mode ......................................9
      5.3. PPP .......................................................10
   6. Using an MPLS Label as the Demultiplexer Field .................11
      6.1. MPLS Shim EXP Bit Values ..................................11
      6.2. MPLS Shim S Bit Value .....................................11
   7. Congestion Control .............................................12
   8. IANA Considerations ............................................12
   9. Security Considerations ........................................12
   10. Normative References ..........................................13
   11. Informative References ........................................13

1.  Introduction

   A PPP/HDLC pseudowire (PW) allows PPP/HDLC Protocol Data Units (PDUs)
   to be carried over an MPLS network.  In addressing the issues
   associated with carrying a PPP/HDLC PDU over an MPLS network, this
   document assumes that a PW has been set up by some means outside the
   scope of this document.  This may be via manual configuration, or
   using a signaling protocol such as that defined in [RFC4447].

   The following figure describes the reference models that are derived
   from [RFC3985] to support the HDLC/PPP PW emulated services.  The
   reader is also assumed to be familiar with the content of the
   [RFC3985] document.

2.  Specification of Requirements

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

Martini, et al.             Standards Track                     [Page 2]
RFC 4618            Transport of PPP/HDLC over MPLS       September 2006

          |<-------------- Emulated Service ---------------->|
          |                                                  |
          |          |<------- Pseudowire ------->|          |
          |          |                            |          |
          |          |    |<-- PSN Tunnel -->|    |          |
          |          V    V                  V    V          |
          V   AC     +----+                  +----+    AC    V
    +-----+    |     | PE1|==================| PE2|     |    +-----+
    |     |----------|............PW1.............|----------|     |

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