[Docs] [txt|pdf] [Tracker] [WG] [Email] [Nits]

Versions: 00 01 02 03 04 05 06 draft-ietf-pwe3-oam-config

MPLS Working Group                                              F. Zhang
Internet-Draft                                                     B. Wu
Intended status: Informational                                    X. Dai
Expires: April 18, 2010                                  ZTE Corporation
                                                        October 15, 2009


            LDP Extensions for MPLS-TP PW OAM configuration
                  draft-zhang-mpls-tp-pw-oam-config-00

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
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on April 18, 2010.

Copyright Notice

   Copyright (c) 2009 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
   Provisions Relating to IETF Documents in effect on the date of
   publication of this document (http://trustee.ietf.org/license-info).
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.

Abstract

   This document describes a procedure for the configuration of the
   pseudo wire (PW) virtual circuit connectivity verification (VCCV)



Zhang, et al.            Expires April 18, 2010                 [Page 1]


Internet-Draft        LDP extensions for TP PW OAM          October 2009


   Bidirectional Forwarding Detection (BFD) OAM mechanism through LDP
   extensions.  As the other MPLS-TP PW OAM functionalities develop, the
   procedure may be changed to cover them.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Conventions used in this document  . . . . . . . . . . . . . .  3
   3.  LDP extensions . . . . . . . . . . . . . . . . . . . . . . . .  3
     3.1.  Operation overviews  . . . . . . . . . . . . . . . . . . .  4
     3.2.  OAM configuration TLV  . . . . . . . . . . . . . . . . . .  4
     3.3.  BFD CC OAM Configuration TLV . . . . . . . . . . . . . . .  5
       3.3.1.  Local Discriminator sub-TLV  . . . . . . . . . . . . .  6
     3.4.  BFD CC&CV OAM Configuration TLV  . . . . . . . . . . . . .  6
       3.4.1.  MEP_IDs  . . . . . . . . . . . . . . . . . . . . . . .  7
       3.4.2.  ME_IDs . . . . . . . . . . . . . . . . . . . . . . . .  8
         3.4.2.1.  IP Compatible ME-IDs . . . . . . . . . . . . . . .  8
         3.4.2.2.  ICC-based ME_IDs . . . . . . . . . . . . . . . . .  8
   4.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  9
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . .  9
   6.  Acknowledgement  . . . . . . . . . . . . . . . . . . . . . . .  9
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . .  9
     7.1.  Normative references . . . . . . . . . . . . . . . . . . .  9
     7.2.  Informative References . . . . . . . . . . . . . . . . . .  9
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10

























Zhang, et al.            Expires April 18, 2010                 [Page 2]


Internet-Draft        LDP extensions for TP PW OAM          October 2009


1.  Introduction

   This document describes a procedure for the configuration of the PW
   VCCV BFD OAM mechanism through LDP extensions.  As the other MPLS-TP
   PW OAM functionalities develop, the procedure may be changed to cover
   them.

   PW VCCV provides end-to-end fault detection and diagnostics for PWs,
   and currently supports the following OAM mechanisms: ICMP Ping, LSP
   Ping, and BFD, as described in [RFC5085].  BFD has been chosen to
   cover MPLS-TP CC functionality [base-BFD], and an extended version of
   BFD, as described in [BFD-CV], can accomplish both MPLS-TP CC and CV,
   even signal the AC status.  BFD for VCCV supports two modes of
   encapsulation - either IP/UDP encapsulated (with IP/UDP header) or
   PW-ACH encapsulated (with no IP/UDP header).

   The use of the VCCV control channel provides the context, based on
   the MPLS-PW label, required to bind and bootstrap the BFD session to
   a particular PW (FEC), see the analysis in [tp-oam-analysis].  But in
   order to identify certain extreme cases of misconnectivity and fill
   the requirements that the BFD mechanism MUST be the same for LSP,
   (MS-)PW and Section as well as for LSP Tandem Connection and PW
   Tandem Connection [BFD-CV], BFD still needs to use Discriminator
   values to identify the connection being verified at both ends of the
   PW.

   The discriminator values can be statically configured, or signaled
   via LSP-Ping [[tp-ping-bfd-procedure].  According to the requirements
   in [RFC5654], "The MPLS-TP control plane MUST support the
   configuration and modification of OAM maintenance points as well as
   the activation/deactivation of OAM when the transport path or
   transport service is established or modified", it is naturally to
   extend LDP for setting up BFD or BFD extended version in order to
   configure MPLS-TP CC and CV OAM functionalities during the PW setup.


2.  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.


3.   LDP extensions







Zhang, et al.            Expires April 18, 2010                 [Page 3]


Internet-Draft        LDP extensions for TP PW OAM          October 2009


3.1.   Operation overviews

   Below, extension to LDP for setting up BFD or BFD extended version
   are defined in order to configure MPLS-TP CC and CV OAM
   functionalities during the PW setup.  PW signaling [RFC4447] defines
   two FECs used to signal PWs.  Of these, FEC Type 129 along with AII
   Type 2 as defined in [RFC5003] fits the identification requirements
   of MPLS-TP, so the current version of this draft just focus on the
   P2P PW (FEC 129) along with AII type 2, P2MP PW will be studied in
   the future.

   The terms "ingress LER" and "egress LER" will not refer in this
   document to any direction in the forwarding plane, but only to the
   LER triggering the PW setup (ingress LER) and the one receiving the
   mapping message (egress LER).

   During the PW signaling, the Control Plane instance in the ingress
   and the egress LER announces the BFD OAM Configuration TLV (inside
   the interface parameters TLV carried by the mapping message,
   following the VCCV parameter field), which includes the "Local
   Discriminator" sub-TLV.

   During the BFD session the ingress LER will use as "MyDiscriminator"
   the value announced in the "Local Discriminator" (mapping message
   sent) and as "YourDiscriminator" the value received in the "Local
   Discriminator" (mapping message received).

   The interval value of BFD control packets both in transmission and
   reception can be negotiated through BFD session itself, so the
   mapping message does not need to carry these time values.  In the
   case BFD extended version should be configured, the ME ID and MEP ID
   do not need to be carried also, for they can be deduced from the
   advertised FEC(129) TLV, as described in the following sections.

3.2.  OAM configuration TLV

   This TLV, specified in [OAM-CONF-FWK], can be used to select which
   OAM technology/method should be used for the PW here.  [RSVP-TE-OAM]
   defines BFD OAM Type and two types of allowed BFD OAM configuration
   TLV, which can also be used for the PW:

   "BFD CC OAM Configuration TLV" which MUST be used for configuring BFD
   for setting up the proactive MPLS-TP CC OAM tool (TLV type = 4).

   "BFD CC&CV OAM Configuration TLV" which MUST be used for configuring
   BFD for setting up the proactive MPLS-TP CC&CV OAM tool (TLV type =
   5).




Zhang, et al.            Expires April 18, 2010                 [Page 4]


Internet-Draft        LDP extensions for TP PW OAM          October 2009


   In case the receiving LER does not support the CC&CV functionality,
   they must be silently ignored so as not to affect the setup of PW.

3.3.  BFD CC OAM Configuration TLV

   The BFD CC OAM Configuration TLV (depicted below) is defined for BFD
   OAM specific configuration parameters.  The BFD CC OAM Configuration
   TLV is carried as a sub-TLV of the "OAM Configuration TLV" in the
   "Interface Parameter TLV" in mapping messages, following "the VCCV
   parameter field".

   This new TLV accommodates generic BFD OAM information and carries
   sub-TLVs.


           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
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |           Type (4) (IANA)     |           Length              |
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |Vers.|R|         Reserved (set to all 0s)                      |
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |                                                               |
         ~                           sub TLVs                            ~
         |                                                               |
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                  Figure 1: BFD CC OAM Configuration TLV

   Type: indicates a new type, the "BFD CC OAM Configuration TLV" (4)
   (IANA to define).

   Length: indicates the total length including sub-TLVs.

   Version: identifies the BFD protocol version.

   R Flag: Role Flag.  If set, the receiving node is required to act
   with an Active Role as described in [[base-BFD], sect. 6.1].

   The BFD CC OAM Configuration TLV MUST include the following sub-TLVs
   during the mapping message:

   "Local Discriminator" sub-TLV (described in paragraph 3.3.1)







Zhang, et al.            Expires April 18, 2010                 [Page 5]


Internet-Draft        LDP extensions for TP PW OAM          October 2009


3.3.1.  Local Discriminator sub-TLV

   The Local Discriminator sub-TLV is depicted below.


           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
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |           Type (1) (IANA)     |           Length              |
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |                      Local Discriminator                      |
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                   Figure 2: Local Discriminator sub-TLV

   Type: indicates a new type, the Local Discriminator sub TLV (1) (IANA
   to define)

   Length: indicates the total length of the TLV including padding.

   Local Discriminator: A unique, nonzero discriminator value generated
   by the transmitting system and referring to itself, used to
   demultiplex multiple BFD sessions between the same pair of systems.

   This Discriminator will be signaled both by the ingress LSR and the
   egress LSR in the mapping message respectively.

3.4.  BFD CC&CV OAM Configuration TLV

   The BFD CC&CV OAM Configuration TLV (depicted below) is defined for
   BFD OAM specific configuration parameters.  The BFD CC&CV OAM
   Configuration TLV is carried as a sub-TLV of the "OAM Configuration
   TLV" in the "Interface Parameter TLV" in mapping messages, following
   "the VCCV parameter field".

   This new TLV accommodates generic BFD OAM information and carries
   sub-TLVs.













Zhang, et al.            Expires April 18, 2010                 [Page 6]


Internet-Draft        LDP extensions for TP PW OAM          October 2009


           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
          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          |   BFD CC&CV  Type (5) (IANA)  |           Length              |
          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          |Vers.|R|         Reserved (set to all 0s)                      |
          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          |                                                               |
          ~                           sub TLVs                            ~
          |                                                               |
          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                 Figure 3: BFD CC&CV OAM Configuration TLV

   Type: indicates a new type, the "BFD CC&CV OAM Configuration TLV" (5)
   (IANA to define).

   Length: indicates the total length including sub-TLVs.

   Version: identifies the BFD protocol version.

   R Flag: Role Flag.  If set, the receiving node is required to act
   with an Active Role as described in [[base-BFD], sect. 6.1].

   The BFD CC OAM Configuration TLV MUST include the following sub-TLVs
   during the mapping message:

   "Local Discriminator" sub-TLV (described in paragraph 3.3.1)

   The BFD CC&CV OAM Configuration TLV May include the following sub-
   TLVs during the mapping message:

   "ICC based ME-IDs" sub-TLV (described in paragraph 3.4.2)

3.4.1.  MEP_IDs

   In order to automatically generate MEP_IDs for MPLS-TP PWs, this
   draft is apt to use the AII associated with that end of the PW.  The
   AII is composed of three fields.  These are the Global_ID, the
   Prefix, and the AC_ID.  The Global_ID used in this document is
   identical to the Global_ID defined in [RFC5003].  The Node_ID is used
   as the Prefix.  The AC_ID is as defined in [RFC5003].  In this way,
   the definition is in accordance with the suggestion in the draft
   [tp-identifier], and there is no need to carry MEP_ID in the mapping
   message.





Zhang, et al.            Expires April 18, 2010                 [Page 7]


Internet-Draft        LDP extensions for TP PW OAM          October 2009


3.4.2.  ME_IDs

3.4.2.1.  IP Compatible ME-IDs

   In order to automatically generate ME_IDs for MPLS-TP PWs, it is
   convenient to use the corresponding PW identifier.  In an MPLS-TP
   environment, a PW is identified by a set of identifiers which can be
   mapped directly to the elements required by FEC 129 and AII Type 2,
   so there is no need to carry ME_IDs in the mapping messages also.

3.4.2.2.  ICC-based ME_IDs

   ME ID for PWs MAY use the globally unique ICC-based format.  This ME
   ID format MAY be used to identify SME, LME, LTCME, PME and PTCME (as
   defined in [OAM-CONF-FWK]) independently on LER/T-PE addressing
   schemes as well as of the FECs used to identify the PW.


          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
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |        ME ID Type             |       Length = 20             |
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |                                                               |
         +                                                               +
         |                       MEG ID                                  |
         +                     (13 bytes)                                +
         |                                                               |
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         |               |0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0|
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                       Figure 4: ICC-based ME_ID TLV

   ME ID Type: it identifies the specific format, value = TBD.

   Length: indicates the total length and it is set to 20.

   ME ID value: the ME ID is a string of up to thirteen characters, each
   character being either alphabetic (i.e.  A-Z) or numeric (i.e. 0-9)
   characters.  It consists of two subfields: the ICC (as defined in
   section 3) followed by a unique ME ID code (UMC).  The UMC MUST be
   unique within the organization identified by the ICC.

   If the receiving LER does not support this ME ID format, it must be
   silently ignored.




Zhang, et al.            Expires April 18, 2010                 [Page 8]


Internet-Draft        LDP extensions for TP PW OAM          October 2009


4.   IANA Considerations

   TBD.


5.  Security Considerations

   TBD.


6.  Acknowledgement

   The author would like to thank Hongbo Wei for his useful discussion.


7.  References

7.1.  Normative references

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

   [RFC4447]  Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G.
              Heron, "Pseudowire Setup and Maintenance Using the Label
              Distribution Protocol (LDP)", RFC 4447, April 2006.

   [RFC5003]  Metz, C., Martini, L., Balus, F., and J. Sugimoto,
              "Attachment Individual Identifier (AII) Types for
              Aggregation", RFC 5003, September 2007.

   [RFC5085]  Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit
              Connectivity Verification (VCCV): A Control Channel for
              Pseudowires", RFC 5085, December 2007.

   [RFC5654]  Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N.,
              and S. Ueno, "Requirements of an MPLS Transport Profile",
              RFC 5654, September 2009.

7.2.  Informative References

   [BFD-CV]   Fulignoli, A., Boutros, S., and M. Vigoureux, "MPLS-TP BFD
              for Proactive CC-CV and RDI", July 2009.

   [OAM-CONF-FWK]
              Takacs, A., Fedyk, D., and J. He, "OAM Configuration
              Framework and Requirements for GMPLS RSVP-TE", March 2009.

   [RSVP-TE-OAM]



Zhang, et al.            Expires April 18, 2010                 [Page 9]


Internet-Draft        LDP extensions for TP PW OAM          October 2009


              Bellagamba, E., Andersson, L., and P. Skoldstrom, "RSVP-TE
              Extensions for MPLS-TP OAM Configuration", September 2009.

   [base-BFD]
              Katz, D. and D. Ward, "Bidirectional Forwarding
              Detection", February 2009.

   [tp-identifier]
              Bocci, M. and G. Swallow, "MPLS-TP Identifiers",
              July 2009.

   [tp-oam-analysis]
              Sprecher, N., Van Helvoort, H., Bellagamba, E., and Y.
              Weingarten, "MPLS-TP OAM Analysis", October 2009.

   [tp-ping-bfd-procedure]
              Bahadur, N., Aggarwal, R., Nadeau, T., Sprecher, N., and
              Y. Weingarten, "LSP-Ping and BFD for MPLS-TP", July 2009.


Authors' Addresses

   Fei Zhang
   ZTE Corporation
   4F,RD Building 2,Zijinghua Road
   Yuhuatai District,Nanjing 210012
   P.R.China

   Phone: +86 025 52877612
   Email: zhang.fei3@zte.com.cn


   Bo Wu
   ZTE Corporation
   4F,RD Building 2,Zijinghua Road
   Yuhuatai District,Nanjing 210012
   P.R.China

   Phone: +86 025 52877276
   Email: wu.bo@zte.com.cn











Zhang, et al.            Expires April 18, 2010                [Page 10]


Internet-Draft        LDP extensions for TP PW OAM          October 2009


   Xuehui Dai
   ZTE Corporation
   4F,RD Building 2,Zijinghua Road
   Yuhuatai District,Nanjing 210012
   P.R.China

   Phone: +86 025 52877612
   Email: dai.xuehui@zte.com.cn











































Zhang, et al.            Expires April 18, 2010                [Page 11]


Html markup produced by rfcmarkup 1.129d, available from https://tools.ietf.org/tools/rfcmarkup/