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Versions: (draft-sfv-mpls-tp-fault) 00 01 02 03 04 05 06 07 RFC 6427

MPLS Working Group                                       G. Swallow, Ed.
Internet-Draft                                       Cisco Systems, Inc.
Intended status: Standards Track                       A. Fulignoli, Ed.
Expires: January 12, 2012                                       Ericsson
                                                       M. Vigoureux, Ed.
                                                          Alcatel-Lucent
                                                              S. Boutros
                                                     Cisco Systems, Inc.
                                                                 D. Ward
                                                  Juniper Networks, Inc.



                                                           July 11, 2011


                       MPLS Fault Management OAM
                      draft-ietf-mpls-tp-fault-05

Abstract

   This draft specifies OAM messages to indicate service disruptive
   conditions for MPLS based Transport Network Label Switched Paths
   (LSPs).  The notification mechanism employs a generic method for a
   service disruptive condition to be communicated to a Maintenance End
   Point (MEP).  An MPLS Operation, Administration, and Maintenance
   (OAM) channel is defined along with messages to communicate various
   types of service disruptive conditions.

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 12, 2012.

Copyright Notice




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   Copyright (c) 2011 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
   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.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  4
     1.2.  Requirements Language  . . . . . . . . . . . . . . . . . .  4
   2.  MPLS Fault Management Messages . . . . . . . . . . . . . . . .  4
     2.1.  MPLS Alarm Indication Signal . . . . . . . . . . . . . . .  5
       2.1.1.  MPLS Link Down Indication  . . . . . . . . . . . . . .  5
     2.2.  MPLS Lock Report . . . . . . . . . . . . . . . . . . . . .  6
     2.3.  Propagation of MPLS Fault Messages . . . . . . . . . . . .  6
   3.  MPLS Fault Management Channel  . . . . . . . . . . . . . . . .  7
   4.  MPLS Fault Management Message Format . . . . . . . . . . . . .  7
     4.1.  Fault Management Message TLVs  . . . . . . . . . . . . . .  9
       4.1.1.  Interface Identifier TLV . . . . . . . . . . . . . . .  9
       4.1.2.  Global Identifier  . . . . . . . . . . . . . . . . . . 10
   5.  Sending and Receiving Fault Management Messages  . . . . . . . 10
     5.1.  Sending a Fault Management Message . . . . . . . . . . . . 10
     5.2.  Clearing a FM Indication . . . . . . . . . . . . . . . . . 11
     5.3.  Receiving a FM Indication  . . . . . . . . . . . . . . . . 11
   6.  Minimum Implementation Requirements  . . . . . . . . . . . . . 11
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 12
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12
     8.1.  Pseudowire Associated Channel Type . . . . . . . . . . . . 12
     8.2.  MPLS Fault OAM Message Type Registry . . . . . . . . . . . 12
     8.3.  MPLS Fault OAM TLV Registry  . . . . . . . . . . . . . . . 13
   9.  Normative References . . . . . . . . . . . . . . . . . . . . . 13
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14










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1.  Introduction

   In traditional transport networks, circuits such as T1 lines are
   typically provisioned on multiple switches.  When an event that
   causes disruption occurs on any link or node along the path of such a
   transport circuit, OAM indications are generated which may in turn
   suppress alarms and/or activate a backup circuit.  The MPLS based
   Transport Network provides mechanisms equivalent to traditional
   transport circuits.  Therefore a Fault Management (FM) capability
   must be defined for MPLS.  This capability is being defined to meet
   the MPLS-TP requirements as defined in RFC 5654 [1], and the MPLS-TP
   Operations, Administration and Maintenance Requirements as defined in
   RFC 5860 [2].  However, this mechanism is intended to be applicable
   to other aspects of MPLS as well.

   Two broad classes of service disruptive conditions are identified.

   1.  Defect: the situation in which the density of anomalies has
       reached a level where the ability to perform a required function
       has been interrupted.

   2.  Lock: an administrative status in which it is expected that only
       test traffic, if any, and OAM (dedicated to the LSP) can be sent
       on an LSP.

   Within the Defect class, a further category, Fault is identified.  A
   fault is the inability of a function to perform a required action.  A
   fault is a persistent defect.

   This document specifies an MPLS OAM channel called an "MPLS-OAM Fault
   Management (FM)" channel.  A single message format and a set of
   procedures are defined to communicate service disruptive conditions
   from the location where they occur to the endpoints of LSPs which are
   affected by those conditions.  Multiple message types and flags are
   used to indicate and qualify the particular condition.

   Corresponding to the two classes of service disruptive conditions
   listed above, two messages are defined to communicate the type of
   condition.  These are known as:

      Alarm Indication Signal (AIS)

      Lock Report (LKR)








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1.1.  Terminology

   ACH: Associated Channel Header

   CC: Continuity Check

   FM: Fault Management

   GAL: Generic Associated Channel Label

   LOC: Loss of Continuity

   LSP: Label Switched Path

   LSR: Label Switching Router

   MEP: Maintenance Entity Group End Point

   MPLS: Multi-Protocol Label Switching

   MPLS-TP: MPLS Transport Profile

   MS-PW: Multi-Segment Pseudowire

   OAM: Operations, Administration and Maintenance

   PHP: Penultimate Hop Pop

   PW: Pseudowire

   S-PE: PW Switching Provider Edge

   TLV: Type, Length, Value

1.2.  Requirements Language

   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 RFC 2119 [3].


2.  MPLS Fault Management Messages

   This document defines messages to indicate service disruptive
   conditions.  Two messages are defined, Alarm Indication Signal, and
   Lock Report.  These semantics of the individual messages are
   described in subsections below.  Fault OAM messages are applicable to
   Bidirectional Co-Routed LSPs and to Multi-Segment Pseudowires



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   (MS-PW).  As MS-PWs are bidirectional LSPs, for simplicity we use the
   term bidir-LSP to mean both of these.  Applicability to other types
   of LSPs is beyond the scope of this document.

   Fault Management messages are carried in-band of the LSP or MS-PW by
   using the Associated Channel Header (ACH).  For Bidirectional Co-
   Routed LSPs the ACH is identified by the Generic Associated Channel
   Label (GAL) as defined in RFC5586 [4].  To facilitate recognition and
   delivery of Fault Management messages, the Fault Management Channel
   is identified by a unique ACH codepoint.

   Fault OAM messages are generated by intermediate nodes where a bidir-
   LSP is switched and bound to specific server layers based upon static
   configuration or signaling.  When a server (sub-)layer, (e.g. a link
   or bidirectional LSP) used by the bidir-LSP fails, the intermediate
   node sends Fault Management messages, using the bidir-LSP's Fault
   associated channel, downstream to the endpoint of the bidir-LSP.
   Strictly speaking, when a server MEP detects a service disruptive
   condition, Fault Management messages are generated by the convergence
   server-to-client adaptation function.  The messages are sent to the
   client MEPs by inserting them into the affected bidir-LSPs in the
   direction downstream of the fault location.  The message is sent
   periodically until the condition is cleared.

2.1.  MPLS Alarm Indication Signal

   The MPLS Alarm Indication Signal (AIS) message is generated in
   response to detecting defects in the server (sub-)layer.  The AIS
   message SHOULD be sent as soon as the condition is detected.  For
   example, an AIS message may be sent during a protection switching
   event and would cease being sent (or cease being forwarded by the
   protection switch selector) if the protection switch was successful
   in restoring the link.

   The primary purpose of the AIS message is to suppress alarms in the
   layer network above the level at which the defect occurs.  When the
   Link Down Indication is set, the AIS message MAY be used to trigger
   recovery mechanisms.

2.1.1.  MPLS Link Down Indication

   The Link Down Indication (LDI) is communicated by setting the L-flag
   to 1.  The L-flag is set in the AIS message in response to detecting
   a fault in the server layer.  The L-flag MUST NOT be set until the
   defect has been determined to be a fault.  The L-flag MUST be set if
   the defect has been determined to be a fault.  For example during a
   protection switching event the L-flag is not set.  However if the
   protection switch was unsuccessful in restoring the link within the



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   expected repair time, the L-flag MUST be set.

   The setting of the L-flag can be predetermined based on the
   protection state.  For example, if a server layer is protected and
   both the working and protection paths are available, both the active
   and standby server MEPs should be programmed to send AIS with the
   L-flag clear upon detecting a defect condition.  If the server layer
   is unprotected or the server layer is protected but only the active
   path is available, the active server MEP should be programmed to send
   AIS with the L-flag set upon detecting a defect condition.

   The receipt of an AIS message with the L-flag set MAY be treated as
   the equivalent of loss of continuity (LOC) at the client layer.  The
   choice of treatment is related to the rate at which the Continuity
   Check (CC) function is running.  In a normal transport environment,
   CC is run at a high rate in order to detect a failure within 10s of
   milliseconds.  In such an environment, the L-flag MAY be ignored and
   the AIS message is used solely for alarm suppression.

   In more general MPLS environments the CC function may be running at a
   much slower rate.  In this environment, the Link Down Indication
   enables faster switch-over upon a failure occurring along the bidir-
   LSP.

2.2.  MPLS Lock Report

   The MPLS Lock Report (LKR) message is generated when a server
   (sub-)layer entity has been administratively locked.  Its purpose is
   to communicate the locked condition to the client layer entities.
   When a bidir-LSP is administratively locked it is not available to
   carry client traffic.  The purpose of the LKR message is to suppress
   alarms in the layer network above the level at which the
   administrative lock occurs and to allow the clients to differentiate
   the lock condition from a defect condition.  While the primary
   purpose of the LKR message is to suppress alarms, similar to AIS with
   the LDI (L-flag set), the receipt of an LKR message MAY be treated as
   the equivalent of loss of continuity at the client layer.

2.3.  Propagation of MPLS Fault Messages

   If the CC function is disabled, a MEP SHOULD generate AIS messages
   toward any client when when in either the AIS or LCK indication is
   raised.  Note that the L-flag is not automatically propagated, i.e.
   the rules of Section 2.1.1 apply, that is the L-flag is not set until
   a fault has been declared.






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3.  MPLS Fault Management Channel

   The MPLS Fault Management channel is identified by the ACH as defined
   in RFC 5586 [4] with the Channel Type set to the MPLS Fault
   Management (FM) code point = 0xHH.  [HH to be assigned by IANA from
   the PW Associated Channel Type registry.  Note: An early codepoint
   allocation has made: 0x0058 Fault OAM (TEMPORARY - expires
   2011-07-16)] The FM Channel does not use ACH TLVs and MUST NOT
   include the ACH TLV header.  The FM ACH Channel is shown 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |0 0 0 1|Version|   Reserved    | 0xHH Fault Management Channel |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               ~
      ~                  MPLS Fault Management Message                ~
      ~                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       Figure 1: ACH Indication of the MPLS Fault Management Channel

   The first three fields are defined in RFC 5586 [4].

   The Fault Management Channel is 0xHH (to be assigned by IANA).


4.  MPLS Fault Management Message Format

   The format of the Fault Management message is shown 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Vers  | Resvd |   Msg Type    |     Flags     | Refresh Timer |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Total TLV Len |                                               ~
      +-+-+-+-+-+-+-+-+              TLVs                             ~
      ~                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 2: MPLS Fault OAM Message Format

   Version





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      The Version Number is currently 1.

   Reserved

      This field MUST be set to zero on transmission and ignored on
      receipt.

   Message Type

      The Message Type indicates the type of condition as listed in the
      table below.


      Msg Type           Description
      --------           -----------------------------
        0x0              Reserved
        0x1              Alarm Indication Signal (AIS)
        0x2              Lock Report (LKR)

   Refresh Timer

      The maximum time between successive FM messages specified in
      seconds.  The range is 1 to 20.  The value 0 is not permitted.

   Total TLV Length

      The total TLV length is the total of all included TLVs.

   Flags

      Two flags are defined.  The reserved flags in this field MUST be
      set to zero on transmission and ignored on receipt.




             +-+-+-+-+-+-+-+-+
             | Reserved  |L|R|
             +-+-+-+-+-+-+-+-+


                               Figure 3: Flags

      L-flag

         Link Down Indication.  The L-flag only has significance in the
         AIS message.  For the LKR message the L-flag MUST be set to
         zero and ignored on receipt.  See Section 2.1.1 for details on



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         setting this bit.

      R-flag

         The R-flag is normally set to zero.  A setting of one indicates
         the removal of a previously sent FM condition.

4.1.  Fault Management Message TLVs

   TLVs are used in Fault Management messages to carry information that
   may not pertain to all messages as well as to allow for
   extensibility.  The TLVs currently defined are the IF_ID, and the
   Global_ID.

   TLVs (Type-Length-Value tuples) have the following format:


       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      |    Length     |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               .
      |                                                               .
      .                             Value                             .
      .                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                        Figure 4: Fault TLV Format

   Type

      Encodes how the Value field is to be interpreted.

   Length

      Specifies the length of the Value field in octets.

   Value

      Octet string of Length octets that encodes information to be
      interpreted as specified by the Type field.

4.1.1.  Interface Identifier TLV

   The Interface Identifier (IF_ID) TLV carries the IF_ID as defined in
   draft-ietf-mpls-tp-identifiers [5].  The Type is 0x1.  The length is
   0x8.



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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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                    MPLS-TP Node Identifier                    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                    MPLS-TP Interface Number                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



                 Figure 5: Interface Identifier TLV Format

4.1.2.  Global Identifier

   The Global Identifier (Global_ID) TLV carries the Global_ID as
   defined in draft-ietf-mpls-tp-identifiers [5].  The Type is 0x2.  The
   length is 0x4.



       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                   MPLS-TP Global Identifier                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



                  Figure 6: Global Identifier TLV Format


5.  Sending and Receiving Fault Management Messages

5.1.  Sending a Fault Management Message

   Service disruptive conditions are indicated by sending FM messages.
   The message type is set to the value corresponding to the condition.
   The refresh timer is set to the maximum time between successive FM
   messages.  This value MUST NOT be changed on successive FM messages
   reporting the same incident.  If the optional clearing procedures are
   not used, then the default value is 1 second.  Otherwise the default
   value is 20 seconds.

   A Global_ID MAY be included.  If the R-flag clearing procedures are
   to be used, the IF_ID TLV MUST be included.  Otherwise, the IF_ID TLV
   MAY be included.

   The message is then sent.  Assuming the condition persists, the



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   message MUST be retransmitted two more times at an interval of one
   second.  Further retransmissions are made according to the value of
   the refresh timer.  Retransmissions continue until the condition is
   cleared.

5.2.  Clearing a FM Indication

   Ceasing to send FM messages will clear the indication after 3.5 times
   the refresh timer.  To clear an indication more quickly, the
   following procedure is used.  The R-flag of the FM message is set to
   one.  Other fields of the FM message SHOULD NOT be modified.  The
   message is sent immediately and then retransmitted two more times at
   an interval of one second.

5.3.  Receiving a FM Indication

   When a FM message is received, a MEP examines it to ensure that it is
   well formed.  If the message type is reserved or unknown, the message
   is ignored.

   If the R-flag is set to zero, the MEP checks to see if a condition
   matching the message type and IF_ID exists.  If it does not, the
   condition to the message type is entered.  An expiration-timer is set
   to 3.5 times the refresh timer.  If the message type and IF_ID match
   an existing condition, message is considered a refresh and the
   expiration-timer is reset.

   If the R-flag is set to one, the MEP checks to see if a condition
   matching the message type and IF_ID exists.  If it does, that
   condition is cleared.  Otherwise the message is ignored.

   If the expiration-time expires, the condition is cleared.


6.  Minimum Implementation Requirements

   At a minimum an implementation MUST support the following:

   1.  Sending AIS and LKR messages at a rate of 1 per second.

   2.  Support of setting the L-flag to indicated a fault.

   3.  Receiving AIS and LKR messages with any allowed Refresh Timer
       value.

   The following items are optional to implement.





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   1.  Sending AIS and LKR message with other values of the Refresh
       Timer other than 1 second.

   2.  Support of receiving the L-flag.

   3.  Support of setting the R-flag to a value other than zero.

   4.  Support of receiving the R-flag.

   5.  All TLVs.


7.  Security Considerations

   Spurious fault OAM messages form a vector for a denial of service
   attack.  However, since these messages are carried in a control
   channel, except of one case discussed below, one would have to gain
   access to a node providing the service in order to effect such an
   attack.  Since transport networks are usually operated as a walled
   garden, such threats are less likely.  If external MPLS traffic is
   mapped to a bidirectional LSP via PHP forwarding operation, it is
   possible to insert a GAL label followed by a fault OAM message.  In
   such a situation an operator SHOULD filter any frames with the GAL
   label at the top of the label stack.


8.  IANA Considerations

8.1.  Pseudowire Associated Channel Type

   Fault OAM requires a unique Associated Channel Type which are
   assigned by IANA from the Pseudowire Associated Channel Types
   Registry.

   Registry:
   Value        Description              TLV Follows  Reference
   -----------  -----------------------  -----------  ---------
   0xHHHH       Fault OAM                No           (This Document)

8.2.  MPLS Fault OAM Message Type Registry

   This sections details the MPLS Fault OAM TLV Registry, a new name
   spaces to be managed by IANA.  The Type space is divided into
   assignment ranges; the following terms are used in describing the
   procedures by which IANA allocates values: "Standards Action" (as
   defined in RFC 5226 [6]) and "Private Use".

   MPLS Fault OAM Message Types take values in the range 0-255.



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   Assignments in the range 0-251 are via Standards Action; values in
   the range 251-255 are for Private Use, and MUST NOT be allocated.

   Message Types defined in this document are:

      Msg Type           Description
      --------           -----------------------------
        0x0              Reserved
        0x1              Alarm Indication Signal (AIS)
        0x2              Lock Report (LKR)

8.3.  MPLS Fault OAM TLV Registry

   This sections details the MPLS Fault OAM TLV Registry, a new name
   spaces to be managed by IANA.  The Type space is divided into
   assignment ranges; the following terms are used in describing the
   procedures by which IANA allocates values: "Standards Action" (as
   defined in RFC 5226 [6]), "Specification Required" and "Private Use".

   MPLS Fault OAM TLVs which take values in the range 0-255.
   Assignments in the range 0-191 are via Standards Action; assignments
   in the range 192-248 are made via "Specification Required"; values in
   the range 248-255 are for Private Use, and MUST NOT be allocated.

   TLVs defined in this document are:

      Value    TLV Name
      -----    -------
          0    Reserved
          1    Interface Identifier TLV
          2    Global Identifier


9.  Normative References

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

   [2]  Vigoureux, M., Ward, D., and M. Betts, "Requirements for
        Operations, Administration, and Maintenance (OAM) in MPLS
        Transport Networks", RFC 5860, May 2010.

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

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



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   [5]  Bocci, M., Swallow, G., and E. Gray, "MPLS-TP Identifiers",
        draft-ietf-mpls-tp-identifiers-06 (work in progress), June 2011.

   [6]  Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
        Considerations Section in RFCs", BCP 26, RFC 5226, May 2008.


Authors' Addresses

   George Swallow (editor)
   Cisco Systems, Inc.
   300 Beaver Brook Road
   Boxborough, Massachusetts  01719
   United States

   Email: swallow@cisco.com


   Annamaria Fulignoli (editor)
   Ericsson

   Email: annamaria.fulignoli@ericsson.com


   Martin Vigoureux (editor)
   Alcatel-Lucent
   Route de Villejust
   Nozay,   91620
   France

   Email: martin.vigoureux@alcatel-lucent.com


   Sami Boutros
   Cisco Systems, Inc.
   3750 Cisco Way
   San Jose, California  95134
   USA

   Email: sboutros@cisco.com


   David Ward
   Juniper Networks, Inc.

   Email: dward@juniper.net





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   Stewart Bryant
   Cisco Systems, Inc.
   250, Longwater
   Green Park, Reading  RG2 6GB
   UK

   Email: stbryant@cisco.com


   Siva Sivabalan
   Cisco Systems, Inc.
   2000 Innovation Drive
   Kanata, Ontario  K2K 3E8
   Canada

   Email: msiva@cisco.com



































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