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Versions: 00 draft-ietf-mpls-lsp-ping-mpls-tp-oam-conf

MPLS Working Group                                    E. Bellagamba, Ed.
Internet-Draft                                         L. Andersson, Ed.
Intended status: Standards Track                                Ericsson
Expires: January 3, 2011                              P. Skoldstrom, Ed.
                                                                Acreo AB
                                                                 D. Ward
                                                                 Juniper
                                                            July 2, 2010


  Configuration of pro-active MPLS-TP Operations, Administration, and
               Maintenance (OAM) Functions Using LSP Ping
              draft-absw-mpls-lsp-ping-mpls-tp-oam-conf-00

Abstract

   This specification describes the configuration of pro-active MPLS-TP
   Operations, Administration, and Maintenance (OAM) Functions for a
   given LSP using a common set of TLVs that is carried on LSP Ping.

Status of this Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on January 3, 2011.

Copyright Notice

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



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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.1.  Contributing Authors  . . . . . . . . . . . . . . . . . . . 3
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . . . 3
     1.3.  Overview of BFD OAM operation . . . . . . . . . . . . . . . 4
   2.  Overview of MPLS OAM for Transport Applications . . . . . . . . 4
   3.  Theory of Operations  . . . . . . . . . . . . . . . . . . . . . 5
     3.1.  MPLS OAM Configuration Operation Overview . . . . . . . . . 5
     3.2.  TLVs structure  . . . . . . . . . . . . . . . . . . . . . . 5
     3.3.  MPLS OAM SOURCE MEP-ID TLV for LSP Ping . . . . . . . . . . 6
   4.  BFD OAM configuration errors  . . . . . . . . . . . . . . . . . 6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 7
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     6.1.  Normative References  . . . . . . . . . . . . . . . . . . . 7
     6.2.  Informative References  . . . . . . . . . . . . . . . . . . 8
   Appendix A.  Additional Stuff . . . . . . . . . . . . . . . . . . . 9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 9




























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1.  Introduction

   This document describes the configuration of pro-active MPLS-TP
   Operations, Administration, and Maintenance (OAM) Functions for a
   given LSP using a common set of TLVs that can be carried on either
   RSVP-TE [RFC3209] or LSP Ping [BFD-Ping].  In particular it specifies
   the mechanisms necessary to establish MPLS-TP OAM entities monitoring
   an LSP and defines information elements and procedures to configure
   pro-active MPLS OAM functions.  Initialization and control of on-
   demand MPLS OAM functions are expected to be carried out by directly
   accessing network nodes via a management interface; hence
   configuration and control of on-demand OAM functions are out-of-scope
   for this document.

   Because the Transport Profile of MPLS, by definition [RFC5654], must
   be capable of operating without a control plane, there are two
   options for in-band OAM: by using an NMS or by using LSP-Ping if a
   control plane is not instantiated.

   Pro-active MPLS OAM is based on the Bidirectional Forwarding
   Detection (BFD) protocol [BFD].  Bidirectional Forwarding Detection
   (BFD), as described in [BFD], defines a protocol that provides low-
   overhead, short-duration detection of failures in the path between
   two forwarding engines, including the interfaces, data link(s), and
   to the extent possible the forwarding engines themselves.  BFD can be
   used to track the liveliness and detect data plane failures of
   MPLS-TP point-to-point and might also be extended to p2mp
   connections.

   MPLS Transport Profile (MPLS-TP) describes a profile of MPLS that
   enables operational models typical in transport networks, while
   providing additional OAM, survivability and other maintenance
   functions not currently supported by MPLS.  [MPLS-TP-OAM-REQ] defines
   the requirements for the OAM functionality of MPLS-TP.

   BFD has been chosen to be the basis of pro-active MPLS-TP OAM
   functions.  MPLS-TP OAM extensions for transport applications, for
   which this document specifies the configuration, are specified in
   [BFD-CCCV], [MPLS-PM], and [MPLS-FMS].

1.1.  Contributing Authors

   The editors gratefully acknowledge the contribution of John Drake.

1.2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this



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   document are to be interpreted as described in RFC 2119 [RFC2119].

1.3.  Overview of BFD OAM operation

   BFD is a simple hello protocol that in many respects is similar to
   the detection components of well-known routing protocols.  A pair of
   systems transmits BFD packets periodically over each path between the
   two systems, and if a system stops receiving BFD packets for long
   enough, some component in that particular bidirectional path to the
   neighboring system is assumed to have failed.  Systems may also
   negotiate to not send periodic BFD packets in order to reduce
   overhead.

   A path is only declared to be operational when two-way communication
   has been established between systems, though this does not preclude
   the use of unidirectional links to support bidirectional paths (co-
   routed or bidirectional or associated bidirectional).

   Each system estimates how quickly it can send and receive BFD packets
   in order to come to an agreement with its neighbor about how rapidly
   detection of failure will take place.  These estimates can be
   modified in real time in order to adapt to unusual situations.  This
   design also allows for fast systems on a shared medium with a slow
   system to be able to more rapidly detect failures between the fast
   systems while allowing the slow system to participate to the best of
   its ability.

   The ability of each system to control the BFD packet transmission
   rate in both directions provides a mechanism for congestion control,
   particularly when BFD is used across multiple network hops.

   As recommended in [BFD-CCCV], the BFD tool needs to be extended for
   the proactive CV functionality by the addition of an unique
   identifier in order to meet the requirements.  The document in [BFD-
   CCCV] specifies the BFD extension and behavior to meet the
   requirements for MPLS-TP proactive Continuity Check and Connectivity
   Verification functionality and the RDI functionality as defined in
   [MPLS-TP-OAM-REQ].


2.  Overview of MPLS OAM for Transport Applications

   [MPLS-TP-OAM-FWK] describes how MPLS OAM mechanisms are operated to
   meet transport requirements outlined in [MPLS-TP-OAM-REQ].

   [BFD-CCCV] specifies two BFD operation modes: 1) "CC mode", which
   uses periodic BFD message exchanges with symmetric timer settings,
   supporting Continuity Check, 2) "CV/CC mode" which sends unique



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   maintenance entity identifiers in the periodic BFD messages
   supporting Connectivity Verification as well as Continuity Check.

   [MPLS-PM] specifies mechanisms for performance monitoring of LSPs, in
   particular it specifies loss and delay measurement OAM functions.

   [MPLS-FMS] specifies fault management signals with which a server LSP
   can notify client LSPs about various fault conditions to suppress
   alarms or to be used as triggers for actions in the client LSPs.  The
   following signals are defined: Alarm Indication Signal (AIS), Link
   Down Indication (LDI) and Locked Report (LKR).  To indicate client
   faults associated with the attachment circuits Client Signal Failure
   Indication (CSF) can be used.  CSF is described in [MPLS-TP-OAM-FWK]
   and in the context of this document is for further study.

   [MPLS-TP-OAM-FWK] describes the mapping of fault conditions to
   consequent actions.  Some of these mappings may be configured by the
   operator, depending on the application of the LSP.  The following
   defects are identified: Loss Of Continuity (LOC), Misconnectivity,
   MEP Misconfiguration and Period Misconfiguration.  Out of these
   defect conditions, the following consequent actions may be
   configurable: 1) whether or not the LOC defect should result in
   blocking the outgoing data traffic; 2) whether or not the "Period
   Misconfiguration defect" should result a signal fail condition.


3.  Theory of Operations

3.1.  MPLS OAM Configuration Operation Overview

   Refer to section 3.1 of [RSVP-TE CONF] for the applicability
   scenarios description and their related configurations and
   mechanisms.  In fact, each of them can be completely reused in case
   of LSP Ping configuration as well as already done for RSVP-TE.

   The only exception is that LSP Ping needs an extra TLV to carry the
   information required for the "CV/CC mode" OAM [BFD-CCCV] and defined
   in [MPLS-TP-IDENTIF].  Such information is supplied by an additional
   sub-TLV as defined in section 3.3.

3.2.  TLVs structure

   LSP Ping follows the same TLV structure defined for RSVP-TE in
   [RSVP-TE CONF] from section 3.2 to section 3.6.

   In addition, an extra TLV is defined "MPLS OAM SOURCE MEP-ID TLV" in
   order to supply the information needed for the Connectivity
   Verification functionality.  In fact, RSVP-TE does not need such TLV



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   because it already encodes this information in other mandatory
   objects already included in its messages.

   The MPLS OAM SOURCE MEP-ID TLV is intended to be inserted in the
   scope of the "OAM configuration TLV" together with the othe sub-TLV
   as defined in [RSVP-TE CONF] section 3.2.

3.3.  MPLS OAM SOURCE MEP-ID TLV for LSP Ping

   The "MPLS OAM SOURCE MEP-ID TLV for LSP Ping" depicted below is
   carried as a sub-TLV of the "OAM Configuration TLV" in case LSP Ping
   is used.


        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 (6)  (IANA)    |        Length = 12            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                         SRC NODE ID                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |           TUNNEL ID           |           LSP ID              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type: indicates a new type, the "MPLS OAM SOURCE MEP-ID" (IANA to
   define).

   Length: indicates the TLV total length in octets.

   SRC NODE ID: 32-bit node identifier as defined in [MPLS-TP-IDENTIF].

   TUNNEL ID: a 16-bit unsigned integer unique to the node as defined in
   [MPLS-TP-IDENTIF].

   LSP ID: a 16-bit unsigned integer unique within the Tunnel_ID as
   defined in [MPLS-TP-IDENTIF].


4.  BFD OAM configuration errors

   In addition to error values specified in [OAM-CONF-FWK] and [ETH-OAM]
   this document defines the following values for the "OAM Problem"
   Error Code:

      - "MPLS OAM Unsupported Functionality";

      - "OAM Problem/Unsupported TX rate interval".




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5.  Security Considerations

   The signaling of OAM related parameters and the automatic
   establishment of OAM entities introduces additional security
   considerations to those discussed in [RFC3473].  In particular, a
   network element could be overloaded, if an attacker would request
   liveliness monitoring, with frequent periodic messages, for a high
   number of LSPs, targeting a single network element.

   Security aspects will be covered in more detailed in subsequent
   versions of this document.


6.  References

6.1.  Normative References

   [BFD]      Katz, D. and D. Ward, "Bidirectional Forwarding
              Detection", 2009, <draft-ietf-bfd-base>.

   [MPLS-CSF]
              He, J. and H. Li, "Indication of Client Failure in
              MPLS-TP", 2009, <draft-he-mpls-tp-csf>.

   [MPLS-FMS]
              Swallow, G., Fulignoli, A., and M. Vigoureux, "MPLS Fault
              Management OAM", 2009, <draft-sfv-mpls-tp-fault>.

   [MPLS-PM]  Bryant, S. and D. Frost, "Packet Loss and Delay
              Measurement for the  MPLS Transport Profile", 2009,
              <draft-frost-mpls-tp-loss-delay>.

   [MPLS-TP-IDENTIF]
              Bocci, M. and G. Swallow, "MPLS-TP Identifiers", 2009,
              <draft-swallow-mpls-tp-identifiers>.

   [MPLS-TP-OAM-REQ]
              Vigoureux, M., Ward, D., and M. Betts, "Requirements for
              OAM in MPLS Transport Networks", 2009,
              <draft-ietf-mpls-tp-oam-requirements>.

   [OAM-CONF-FWK]
              Takacs, A., Fedyk, D., and J. van He, "OAM Configuration
              Framework for GMPLS RSVP-TE", 2009,
              <draft-ietf-ccamp-oam-configuration-fwk>.

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



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   [RFC3471]  Berger, L., "Generalized Multi-Protocol Label Switching
              (GMPLS) Signaling Functional Description", RFC 3471,
              January 2003.

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

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

   [RSVP-TE CONF]
              Bellagamba, E., Ward, D., Andersson, L., and P.
              Skoeldstroem, "Configuration of pro-active MPLS-TP
              Operations, Administration, and Maintenance (OAM)
              Functions Using RSVP-TE", 2010,
              <draft-ietf-ccamp-rsvp-te-mpls-tp-oam-ext>.

6.2.  Informative References

   [BFD-CCCV]
              Fulignoli, A., Boutros, S., and M. Vigoreux, "MPLS-TP BFD
              for Proactive CC-CV and RDI", 2009,
              <draft-asm-mpls-tp-bfd-cc-cv>.

   [BFD-Ping]
              Bahadur, N., Aggarwal, R., Ward, D., Nadeau, T., Sprecher,
              N., and Y. Weingarten, "LSP-Ping and BFD encapsulation
              over ACH", 2009,
              <draft-nitinb-mpls-tp-lsp-ping-bfd-procedures-02>.

   [ETH-OAM]  Takacs, A., Gero, B., Fedyk, D., Mohan, D., and D. Long,
              "GMPLS RSVP-TE Extensions for Ethernet OAM", 2009,
              <draft-ietf-ccamp-rsvp-te-eth-oam-ext>.

   [LSP Ping]
              Kompella, K. and G. Swallow, "Detecting Multi-Protocol
              Label Switched (MPLS) Data Plane Failures", 2006, <RFC
              3479>.

   [MPLS-TP OAM Analysis]
              Sprecher, N., Nadeau, T., van Helvoort, H., and
              Weingarten, "MPLS-TP OAM Analysis", 2006,
              <draft-sprecher-mpls-tp-oam-analysis>.

   [MPLS-TP-FWK]
              Bocci, M., Bryant, S., Frost, D., and L. Levrau, "OAM
              Configuration Framework for GMPLS RSVP-TE", 2009,



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              <draft-ietf-mpls-tp-framework>.

   [MPLS-TP-OAM-FWK]
              Busi, I. and B. Niven-Jenkins, "MPLS-TP OAM Framework and
              Overview", 2009, <draft-ietf-mpls-tp-oam-framework>.

   [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.


Appendix A.  Additional Stuff

   This becomes an Appendix.


Authors' Addresses

   Elisa Bellagamba (editor)
   Ericsson
   Farogatan 6
   Kista,   164 40
   Sweden

   Phone: +46 761440785
   Email: elisa.bellagamba@ericsson.com


   Loa Andersson (editor)
   Ericsson
   Farogatan 6
   Kista,   164 40
   Sweden

   Phone:
   Email: loa.andersson@ericsson.com


   Pontus Skoldstrom (editor)
   Acreo AB
   Electrum 236
   Kista,   164 40
   Sweden

   Phone: +46 8 6327731
   Email: pontus.skoldstrom@acreo.se





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   Dave Ward
   Juniper


   Phone:
   Email: dward@juniper.net













































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