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Versions: 00 01 02 draft-ietf-mpls-tp-lsp-ping-bfd-procedures

Network Working Group                                    N. Bahadur, Ed.
Internet-Draft                                          R. Aggarwal, Ed.
Intended status: Standards Track                            D. Ward, Ed.
Expires: August 20, 2010                          Juniper Networks, Inc.
                                                               T. Nadeau
                                                                      BT
                                                             N. Sprecher
                                                           Y. Weingarten
                                                  Nokia Siemens Networks
                                                       February 16, 2010


                LSP-Ping and BFD encapsulation over ACH
            draft-nitinb-mpls-tp-lsp-ping-bfd-procedures-02

Abstract

   LSP-Ping and BFD for MPLS are existing and widely deployment OAM
   mechanisms for MPLS LSPs.  This document describes ACH encapsulation
   for LSP-Ping, to enable use of LSP-Ping when IP addressing is not in
   use.  This document also clarifies the use of BFD for MPLS LSPs using
   ACH encapsulation, when IP addressing may not be available and/or it
   may not be desirable to encapsulate BFD packets in IP.

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
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   The list of Internet-Draft Shadow Directories can be accessed at
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   This Internet-Draft will expire on August 20, 2010.

Copyright Notice



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   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   publication of this document.  Please review these documents
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   the Trust Legal Provisions and are provided without warranty as
   described in the BSD License.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.1.  Conventions used in this document . . . . . . . . . . . . . 3
     1.2.  LSP-Ping and BFD over ACH . . . . . . . . . . . . . . . . . 3
   2.  LSP-Ping extensions . . . . . . . . . . . . . . . . . . . . . . 3
     2.1.  LSP-Ping packet over ACH for LSPs . . . . . . . . . . . . . 3
     2.2.  LSP-Ping packet over ACH for PWs  . . . . . . . . . . . . . 4
     2.3.  Source Address TLV  . . . . . . . . . . . . . . . . . . . . 4
     2.4.  MEP and MIP Identifier  . . . . . . . . . . . . . . . . . . 4
   3.  Running BFD over MPLS-TP LSPs . . . . . . . . . . . . . . . . . 5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
     5.1.  New ACH Channel Type  . . . . . . . . . . . . . . . . . . . 6
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 6
     6.1.  Normative References  . . . . . . . . . . . . . . . . . . . 6
     6.2.  Informative References  . . . . . . . . . . . . . . . . . . 7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 7



















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1.  Introduction

   LSP-Ping [RFC4379] and [I-D.ietf-bfd-mpls] are OAM mechanisms for
   MPLS LSPs.  This document describes ACH encapsulation for LSP-Ping,
   to enable use of LSP-Ping when IP addressing is not in use.  When IP
   addressing is in use, procedures specified in [RFC4379] apply as is.
   This document also clarifies the use of BFD for MPLS LSPs using ACH
   encapsulation, when IP addressing may not be available and/or it may
   not be desirable to encapsulate BFD packets in IP.

1.1.  Conventions used in this document

   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].

1.2.  LSP-Ping and BFD over ACH

   In certain MPLS-TP deployment scenarios IP addressing might not be
   available or it may be preferred to use non-IP encapsulation for LSP-
   Ping and BFD packets.  To enable re-use of OAM techniques provided by
   LSP-Ping and BFD in such networks, rest of this document defines
   extensions to LSP-Ping and procedures for using BFD.

   Sections Section 2.1 and Section 2.2 describe a new ACH code-point
   for performing LSP-Ping over ACH.  Section Section 3 describes
   procedures for using BFD over ACH.


2.  LSP-Ping extensions

2.1.  LSP-Ping packet over ACH for LSPs

   [RFC5586] defines an ACH mechanism for MPLS LSPs.  This document
   defines a new ACH channel type for LSP-Ping, when IP addressing is
   not in use, for LSP-Ping over associated bi-directional LSPs and co-
   routed bi-directional LSPs.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |0 0 0 1|Version|   Reserved    |     LSP-Ping Channel Type     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                    Figure 1: LSP-Ping ACH Channel Type

   When ACH header is used, an LSP-Ping packet will look as follows:



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       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                         MPLS Label stack                      |
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                          GAL                                  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |0 0 0 1|Version|   Reserved    |     LSP-Ping Channel Type     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                          ACH TLVs                             |
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      LSP-Ping payload                         |
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                    Figure 2: LSP-Ping packet with ACH

   When using LSP-Ping over the ACH header, the LSP-Ping Reply mode
   [RFC4379] in the LSP-Ping echo request MUST be set to 4 (Reply via
   application level control channel).

2.2.  LSP-Ping packet over ACH for PWs

   [RFC4385] defines an PW-ACH mechanism for pseudowires.  The ACH
   channel type for LSP-Ping defined in Section 2.1 will be re-used for
   pseudowires so that IP addressing is not needed when using LSP-Ping
   OAM over pseudowires.

2.3.  Source Address TLV

   When sending LSP-Ping packets using ACH, without IP encapsulation,
   there MAY be a need to identify the source address of the packet.
   This source address will be specified via the Source Address TLV,
   being defined in [I-D.ietf-mpls-tp-ach-tlv].  Only 1 source address
   TLV MUST be present in a LSP-Ping packet.  The source address MUST
   specify the address of the originator of the packet.  If more than 1
   such TLV is present in a LSP-Ping request packet, then an error of
   "Malformed echo request received" SHOULD be returned.  If more than 1
   source address TLV is present, then the packet SHOULD be dropped
   without further processing.

2.4.  MEP and MIP Identifier

   When sending LSP-Ping packets using ACH, there MAY be a need to
   identify the maintenance end point (MEP) and/or the maintenance



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   intermediate point (MIP) being monitored.  The MEP/MIP identifiers
   defined in [I-D.swallow-mpls-tp-identifiers] can be carried in the
   ACH TLVs [I-D.ietf-mpls-tp-ach-tlv] for identification.


3.  Running BFD over MPLS-TP LSPs

   [I-D.ietf-bfd-mpls] describes how BFD can be used for Continuity
   Check for MPLS LSPs.  When IP addressing is in use, the procedures
   described in [I-D.ietf-bfd-mpls] apply as is.  This section clarifies
   the usage of BFD in the context of MPLS-TP LSPs when it is not
   desirable to use IP encapsulation.  When using BFD over MPLS-TP LSPs,
   the BFD descriminator MAY either be signaled via LSP-Ping or be
   statically configured.  The BFD packets MUST be sent over ACH when IP
   encapsulation is not used.  The ACH Channel type MUST be set to the
   value specified in [I-D.ietf-pwe3-vccv-bfd].  BFD packets, for both
   directions, MUST be sent over the MPLS-TP LSP and IP forwarding
   SHOULD NOT be used for the reverse path.  The format of a BFD packet
   when using it as an OAM tool for MPLS-TP LSPs SHOULD be as follows:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                         MPLS Label stack                      |
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                          GAL                                  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |0 0 0 1|Version|   Reserved    |        Channel Type           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                            ACH TLVs                           |
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                          BFD payload                          |
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                  Figure 3: BFD packet over MPLS-TP LSPs

   [I-D.ietf-pwe3-vccv-bfd] specifies how BFD can be used over MPLS PWs.

   BFD supports continuous fault monitoring and thus meets the pro-
   active Continuity Check and verification requirement specified in
   [I-D.ietf-mpls-tp-oam-requirements].  BFD SHOULD be run pro-actively.
   This function SHOULD be performed between End Points (MEPs) of PWs,
   LSPs and Sections.  For point to multipoint Continuity Check, there
   is work in progress on using BFD for P2MP MPLS LSPs (



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   [I-D.katz-ward-bfd-multipoint]) and this can be leveraged for MPLS-TP
   LSPs as well.  Failure of a BFD session over a LSP can be used to
   trigger protection switching or other fault remedial procedures.

   When sending BFD packets using ACH, there MAY be a need to identify
   the maintenance end point (MEP) and/or the maintenance intermediate
   point (MIP) being monitored.  The MEP/MIP identifiers defined in
   [I-D.swallow-mpls-tp-identifiers] can be carried in the ACH TLVs
   [I-D.ietf-mpls-tp-ach-tlv] for identification.


4.  Security Considerations

   The draft does not introduce any new security considerations.  Those
   discussed in [RFC4379] are also applicable to this document.


5.  IANA Considerations

5.1.  New ACH Channel Type

   A new Channel type is defined in Section 2.1.  IANA is requested to
   assign a new value from the "PW Associated Channel Type" registry, as
   per IETF consensus policy.

       Value    Meaning
       -----    -------
        TBD     Associated Channel carries LSP-Ping packet



6.  References

6.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4379]  Kompella, K. and G. Swallow, "Detecting Multi-Protocol
              Label Switched (MPLS) Data Plane Failures", RFC 4379,
              February 2006.

   [RFC4385]  Bryant, S., Swallow, G., Martini, L., and D. McPherson,
              "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for
              Use over an MPLS PSN", RFC 4385, February 2006.






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6.2.  Informative References

   [I-D.ietf-bfd-mpls]
              Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
              "BFD For MPLS LSPs", draft-ietf-bfd-mpls-07 (work in
              progress), June 2008.

   [I-D.ietf-mpls-tp-ach-tlv]
              Boutros, S., Bryant, S., Sivabalan, S., Swallow, G., and
              D. Ward, "Definition of ACH TLV Structure",
              draft-ietf-mpls-tp-ach-tlv-01 (work in progress),
              February 2010.

   [I-D.ietf-mpls-tp-oam-requirements]
              Vigoureux, M., Ward, D., and M. Betts, "Requirements for
              OAM in MPLS Transport Networks",
              draft-ietf-mpls-tp-oam-requirements-04 (work in progress),
              December 2009.

   [I-D.ietf-pwe3-vccv-bfd]
              Nadeau, T. and C. Pignataro, "Bidirectional Forwarding
              Detection (BFD) for the Pseudowire Virtual Circuit
              Connectivity Verification (VCCV)",
              draft-ietf-pwe3-vccv-bfd-07 (work in progress), July 2009.

   [I-D.katz-ward-bfd-multipoint]
              Katz, D. and D. Ward, "BFD for Multipoint Networks",
              draft-katz-ward-bfd-multipoint-02 (work in progress),
              February 2009.

   [I-D.swallow-mpls-tp-identifiers]
              Bocci, M. and G. Swallow, "MPLS-TP Identifiers",
              draft-swallow-mpls-tp-identifiers-02 (work in progress),
              October 2009.

   [RFC5586]  Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic
              Associated Channel", RFC 5586, June 2009.














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Authors' Addresses

   Nitin Bahadur (editor)
   Juniper Networks, Inc.
   1194 N. Mathilda Avenue
   Sunnyvale, CA  94089
   US

   Phone: +1 408 745 2000
   Email: nitinb@juniper.net
   URI:   www.juniper.net


   Rahul Aggarwal (editor)
   Juniper Networks, Inc.
   1194 N. Mathilda Avenue
   Sunnyvale, CA  94089
   US

   Phone: +1 408 745 2000
   Email: rahul@juniper.net
   URI:   www.juniper.net


   David Ward (editor)
   Juniper Networks, Inc.
   1194 N. Mathilda Avenue
   Sunnyvale, CA  94089
   US

   Phone: +1 408 745 2000
   Fax:
   Email: dward@juniper.net
   URI:   www.juniper.net


   Thomas D. Nadeau
   BT
   BT Centre
   81 Newgate Street
   London  EC1A 7AJ
   United Kingdom

   Email: tom.nadeau@bt.co







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   Nurit Sprecher
   Nokia Siemens Networks
   3 Hanagar St. Neve Ne'eman B
   Hod Hasharon  45241
   Israel

   Phone: +972-9-775 1229
   Email: nurit.sprecher@nsn.com


   Yaacov Weingarten
   Nokia Siemens Networks
   3 Hanagar St. Neve Ne'eman B
   Hod Hasharon  45241
   Israel

   Phone: +972-9-775 1827
   Email: yaacov.weingarten@nsn.com

































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