Network Working Group                                           W. Cheng
Internet-Draft                                                   L. Wang
Intended status: Standards Track                                   H. Li
Expires: April 30, 2015                                     China Mobile
                                                                  K. Liu
                                                     Huawei Technologies
                                                               S. Davari
                                                    Broadcom Corporation
                                                                 J. Dong
                                                     Huawei Technologies
                                                         A. D'Alessandro
                                                          Telecom Italia
                                                        October 27, 2014


     Dual-Homing Coordination for MPLS Transport Profile (MPLS-TP)
                              Pseudowires
          draft-cheng-pwe3-mpls-tp-dual-homing-coordination-00

Abstract

   In some scenarios, the MPLS Trasport Profile (MPLS-TP) Pseudowires
   (PWs) are provisioned through either static configuration or
   management plane, where a dynamic control plane is not available.  A
   fast protection mechanism for MPLS-TP PWs is needed to protect
   against the failure of Attachment Circuit (AC), the failure of
   Provider Edge (PE) and also the failure in the Packet Switched
   Network (PSN).  The framework and scenarios for dual-homing
   pseudowire (PW) local protection are described in [draft-cheng-pwe3-
   mpls-tp-dual-homing-protection].  This document proposes a dual-
   homing coordination mechanism for MPLS-TP PWs, which is used for
   state exchange and coordination between the dual-homing PEs for dual-
   homing PW local protection.

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 [RFC2119].

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




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   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 April 30, 2015.

Copyright Notice

   Copyright (c) 2014 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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Overview of the Proposed Solution . . . . . . . . . . . . . .   3
   3.  Protocol Extensions for MPLS-TP PW Dual-Homing Protection . .   4
     3.1.  Information Exchange Between Dual-Homing PEs  . . . . . .   4
     3.2.  Protection Procedures . . . . . . . . . . . . . . . . . .   7
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   [RFC6372] and [RFC6378] describe the framework and mechanism of MPLS-
   TP Linear protection, which can provide protection for the MPLS LSP
   or PW between the edge nodes.  Such mechanism does not protect the
   failure of the Attachement Circuit (AC) or the endpoint nodes.

   In some scenarios such as mobile backhauling, the MPLS PWs are
   provisioned with dual-homing topology, in which at least the CE node



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   in one side is dual-homed to two PEs.  If a failure occurs in the
   primary AC, operators usually prefer to perform switchover only in
   the dual-homing PE side and keep the working pseudowire unchanged if
   possible.  This is to avoid massive PW switchover in the mobile
   backhaul network due to the AC failure in the core site, and also
   could achieve efficient and balanced link bandwidth utilization.
   Similarly, it is preferable to keep using the working AC when one
   working PW fails in PSN network.  A fast dual-homing PW protection
   mechanism is needed to protect the failure in AC, the the PE node and
   the PSN network to meet the above requirements.

   [I-D.cheng-pwe3-mpls-tp-dual-homing-protection] describes a framework
   and several scenarios for dual-homing pseudowire (PW) local
   protection.  This document proposes a dual-homing coordination
   mechanism for static MPLS-TP PWs, which is used for information
   exchange and coordination between the dual-homing PEs for the dual-
   homing PW local protection.  The proposed mechanism has been deployed
   in several mobile backhaul networks which use static MPLS-TP PWs for
   the backhauling of mobile traffic from the RF sites to the core site.

2.  Overview of the Proposed Solution

   The linear protection mechanisms for MPLS-TP network are defined in
   [RFC6378], [RFC7271] and [RFC7324].  When such mechanisms are applied
   to PW linear protection, both the working PW and the protection PW
   terminate on the same PE nodes.  In order to provide dual-homing
   protection for MPLS-TP PWs, some additional mechanisms are needed.

   In MPLS-TP PW dual-homing protection, the linear protection
   mechanisms on the single-homing PE (e.g.  PE3 in figure 3) are not
   changed, while on the dual-homing side, the working PW and protection
   PW are terminated on two dual-homing PEs (e.g.  PE1 and PE2 in figure
   1) respectively to protect the failure occurs in the dual-homing PEs
   and the connected ACs.  As specified in
   [I-D.cheng-pwe3-mpls-tp-dual-homing-protection], a dedicated Dual-
   Node Interconnection (DNI) PW is provisioned between the two dual-
   homing PE nodes, which is used to bridge the traffic between the
   dual-homing PEs when failure happens in the working PW or the primary
   AC.  In order to make the linear protection mechanism work in the
   dual-homing PEs scenario, some coordination between the dual-homing
   PE nodes is needed, so that the dual-homing PEs can set the
   connection between AC, the service PW and the DNI-PW properly in a
   coordinated fasion.








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               +----------------+
               /                |                +--------+
          AC1 /|   PE1          |  Working PW    |        |
             / |                X----------------X        |
            /  |                |  Service PW1   |        |
       +---/+  +--------X-------+                |        |   +----+
       |    |           | DNI PW                 |  PE3   |   |    |
       | CE1|           |                        |        |---| CE2|
       +---\+  +--------X-------+                |        |   +----+
            \  |                | Protection PW  |        |
             \ |                X----------------X        |
          AC2 \|                | Service PW2    |        |
               \   PE2          |                +--------+
               +----------------+

              Figure 1. Dual-homing Proctection with DNI-PW

3.  Protocol Extensions for MPLS-TP PW Dual-Homing Protection

   In dual-homing MPLS-TP PW local protection, the forwarding state of
   the dual-homing PEs are determined by the forwarding state machine as
   defined in [I-D.cheng-pwe3-mpls-tp-dual-homing-protection].  In order
   to achieve the MPLS-TP PW dual-homing protection, coordination
   between the dual-homing PE nodes is needed to exchange the PW status
   and protection coordination requests.

3.1.  Information Exchange Between Dual-Homing PEs

   The coordination information will be sent over the G-ACh as described
   in [RFC5586].  A new G-ACh channel type is defined for the
   coordination between the dual-homing PEs of MPLS-TP PWs.  This
   channel type can be used for the exchange of different kinds of
   information between the dual-homing PEs.  This document uses this
   channel type for the PW status exchange and switchover coordination
   between the dual-homing PEs.  Other potential usage of this channel
   type are for further study and are out of the scope of this document.

   The MPLS-TP Dual-Homing Coordination (DHC) message is sent on the DNI
   PW between the dual-homing PEs.  The format of MPLS-TP DHC message is
   shown below:











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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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0 0 0 1|Version|     Flags     |         DHC Code Point        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Dual-Homing Group ID                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         TLV  Length           |           Reserved            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~                              TLVs                             ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          Figure 2. MPLS-TP Dual-Homing Coordination Message

   The Dual-Homing Group ID is a 4-octet unsigned integer to identify
   the dual-homing PEs in the same dual-homing group.

   In this document, 2 TLVs are defined in MPLS-TP Dual-Homing
   Coordination message for dual-homing MPLS-TP PW protection:

   Type        Description               Length
    1          PW Status                 20 Bytes
    2        Dual-Node Switching         16 Bytes

   The PW Status TLV is used by a dual-homing PE to report its service
   PW status to the other dual-homing PE in the same dual-homing group.

      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 (PW Status)        |          Length               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Destination Node_ID                       |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       Source Node_ID                          |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         DNI PW-ID                             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Reserved                            |P|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      Service PW State                     |D|F|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                       Figure 3. PW Status TLV

   - The Destination Node_ID is the 32-bit Node_ID of the receiver PE.

   - The Source Node_ID is the 32-bit Node_ID of the sending PE.

   - The DNI PW-ID field contains the 32-bit PW-ID of the DNI PW.



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   - The P (Protection) bit indicates whether the message is sent by the
   working PE (P=0) or by the protection PE (P=1).

   - The Service PW State field indicates the state of the Service PW
   between the sending PE and the remote PE.  Currently two bits are
   defined in the Service PW Request field:

   o  F bit: Indicates Signal Fail (SF) is generated on the service PW.
      It can be either a local request or a remote request received from
      the remote PE.

   o  D bit: Indicates Signal Degrade (SD) generated on the service PW.
      It can be either a local request or a remote request received from
      the remote PE.

   o  Other bits are reserved and MUST be set to 0 on transmission and
      SHOULD be ignored upon receipt.

   The Dual-Node Switching TLV is used by the protection dual-homing PE
   to send protection state coordination to the working dual-homing PE.

      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=2 (Dual-Node Switching) |          Length               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Destination Node_ID                       |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       Source Node_ID                          |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         DNI PW-ID                             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          Reserved                         |S|P|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                      Figure 4. Dual-node Switching TLV

   - The Destination Node_ID is the 32-bit Node_ID of the receiving PE.

   - The Source Node_ID is the 32-bit Node_ID of the sending PE.

   - The DNI PW-ID field contains PW-ID of the DNI PW.

   - The P (Protection) bit indicates whether the message is sent by the
   working PE (P=0) or by the protection PE (P=1).  With the mechanism
   described in this document, only the protection PE could send DHC
   message with the Dual-node Switching TLV.





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   - The S (PW Switching) bit indicates which service PW is used for
   transporting user traffic.  It is set to 0 when traffic is
   transported on the working PW, and is set to 1 if traffic will be
   transported on the protection PW.  The value of the S bit is
   determined by the protection coordination mechanism between the dual-
   homing protection PE and the remote PE.

   The MPLS-TP DHC message is exchanged periodically between the dual-
   homing PEs.  Whenever there is a change in the status of service PW
   on one dual-homing PE, it MUST be sent to the other dual-homing PE
   immediately using the PW status TLV in the DHC message.  The Dual-
   Node Switching TLV is carried in the DHC message when a switchover
   request is issued by the protection PE according to the dual-homing
   forwarding state machine.

3.2.  Protection Procedures

   The dual-homing MPLS-TP PW protection mechanism can be deployed with
   the existing AC redundancy mechanisms, e.g.  Multi-Chassis Link
   Aggregation Group (MC-LAG).  On the PSN network side, PSN tunnel
   protection mechanism is not required, as the dual-homing PW
   protection can also protect the failure occurs in the PSN network.

   On the single-homing PE side, it just treats the working PW and
   protection PW as if they terminate on the same remote PE node, thus
   normal MPLS-TP protection coordination mechanisms still apply to the
   single-homing PE.

   The forwarding behavior of the dual-homing PEs is determined by the
   components shown in the figure below:





















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             +----------------------------------+           +-----+
             |        PE1 (Working PE)          |           |     |
             +----------------------------------+           |     |
             |                 |                |    PW1    |     |
             +    Forwarder    +     Service    X<--------->X     |
            /|                 |       PW       |  Working  |     |
           / +--------+--------+                |    PW     |     |
     AC1  /  |     DNI PW      |                |           |     |
         /   +--------X--------+----------------+           |     |
 +-----+/             ^                                     |     |
 | CE1 |              |  DNI PW                             | PE3 | +---+
 +-----+              |                                     |     --|CE3|
        \             V                                     |     | +---+
     AC2 \   +--------X--------+----------------+           |     |
          \  |     DNI PW      |                |           |     |
           \ +--------+--------+                |           |     |
            \|                 |     Service    |    PW2    |     |
             +    Forwarder    +       PW       X<--------->X     |
             |                 |                | Protection|     |
             +----------------------------------+     PW    |     |
             |        PE2 (Protection PE)       |           |     |
             +----------------------------------+           +-----+
            Figure 5. Components of PW dual-homing protection

   In figure 5, for a dual-homing PE, service PW is the PW used to
   carriy service between the dual-homing PE and the remote PE.  The
   status of service PW is determined by the OAM mechanism between the
   dual-homing PE and the remote PE.

   DNI PW is the PW established between the two dual-homing PE nodes.
   It is used to bridge traffic when failure occurs in the PSN network
   or in the ACs.  The status of DNI PW is determined by OAM mechanism
   running between the dual-homing PEs.  Since DNI PW is used to carry
   both the coordination messages and service traffic, it is RECOMMENDED
   to provision multiple links between the dual-homing PEs.

   AC is the link which connects the dual-homing PEs to the dual-homed
   CE.  The status of AC is determined by MC-LAG or other AC redundancy
   mechanisms.

   In order to perform dual-homing PW local protection, the service PW
   status and protection coordination requests need to be exchanged
   between the dual-homing PEs using the DHC message defined above.

   Whenever there is a change in the status of service PW on the dual-
   homing PE, it MUST be sent to the other dual-homing PE in the same
   dual-homing group immediately using the PW status TLV in the DHC
   message.  After the exchange of PW status, both the dual-homing PEs



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   could obtain the status of the working and protection service PWs.
   The status of DNI PW is determined by the OAM mechanisms between the
   dual-homing PEs, and the status of AC is determined by the AC
   redundancy mechansim.  The protection PE SHOULD make the switchover
   decision acording to the status of the connected AC, service PW and
   DNI PW, and SHOULD send the switchover request to the working PE
   using the Dual-node switching TLV in the DHC message.  The forwarding
   behavoir of the dual-homing PE nodes is determined by the forwarding
   state machine as shown in the following table:

          +-----------+---------+--------+---------------------+
          |Service PW |   AC    | DNI PW | Forwarding Behavior |
          +-----------+---------+--------+---------------------+
          |  Active   | Active  |   Up   |Service PW <-> AC    |
          +-----------+---------+--------+---------------------+
          |  Active   | Standby |   Up   |Service PW <-> DNI PW|
          +-----------+---------+--------+---------------------+
          |  Standby  | Active  |   Up   |    DNI PW <-> AC    |
          +-----------+---------+--------+---------------------+
          |  Standby  | Standby |   Up   |  Drop all packets   |
          +-----------+---------+--------+---------------------+
             Table 1. Dual-homing PE Forwarding State Machine

   Using the topology in figure 5 as an example, in normal state, the
   working PW (PW1) is in active state, the protection PW (PW2) is in
   standby state, the DNI PW is up, and AC1 is in active state according
   to AC side redundancy mechanism.  According to Table 1, traffic will
   be forwarded through the working PW (PW1) and the primary AC (AC1).
   No traffic will go through the protection PE (PE2) or the DNI PW, as
   both the protection PW (PW2) and the AC connecting to PE2 are in
   standby state.

   If some failure occurs in AC1, the state of AC2 changes to active
   according to the AC redundancy mechanism, while there is no change in
   the status of the working and protection PW.  According to the
   forwarding state machine in Table 1, PE1 starts to forward traffic
   between the working PW and the DNI PW, while PE2 starts to forward
   traffic between AC2 and the DNI PW.  It should be noted that in this
   case only AC switchover takes place, in PSN network the traffic is
   still fowarded using the working PW, PW switchover is not needed.

   If some failure occurs in the PSN network which causes PW1 down, the
   working PE (PE1) or the remote PE (PE3) can detect the failure using
   MPLS-TP OAM mechanism.  If PE1 detects the failure, it MUST inform
   PE2 the status of the working PW using the PW Status TLV in MPLS-TP
   DHC message.  According to the forwarding state machine in Table 1,
   PE2 SHOULD set the connection between PW2 and the DNI PW, and PE1
   SHOULD set the connection between the DNI PW and AC1.  For switchover



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   coordination, PE2 MUST send a DHC message to PE1 with the S bit in
   the Dual-node switching TLV set, and send an appropriate protection
   coordination message on the protection PW (PW2) to PE3 for the remote
   side switchover from PW1 to PW2.  Upon receipt of Dual-node switching
   TLV in the DHC message, PE1 MUST switch the traffic onto the
   connection between DNI PW and AC1.  If PE3 detects the failure in
   PW1, it would send a protection coordination message on the
   protection PW (PW2) to inform PE2 to switchover to the protection PW.
   And PE2 MUST send a DHC message to PE1 with the S bit in the Dual-
   node switching TLV set to coordinate the switchover on PE1 and PE2.

   If some failure causes the working PE (PE1) down, both the remote
   PE(PE3) and the protection PE(PE2) would detect the failure using
   MPLS-TP OAM mechanisms.  The status of AC1 changes to standby, and
   the state of AC2 changes to active according to AC redundancy
   mechansim.  PE3 would send a protection coordination message on the
   protection path to inform its peer node (PE2) to switchover to the
   protection PW.  According to the forwarding state machine in Table 1,
   PE2 starts to forward traffic between the protection PW and AC2.

4.  IANA Considerations

   IANA needs to assign one new channel type for "MPLS-TP Dual-Homing
   Coordination messgae" from the "Pseudowire Associated Channel Types"
   registry.

   This document creates a new registry called "MPLS-TP DHC TLVs"
   registry. 2 new TLVs are defined in this document:

   Type        Description               Length
    1          PW Status                 20 Bytes
    2        Dual-Node Switching         16 Bytes

5.  Security Considerations

   Procedures and protocol extensions defined in this document do not
   affect the security model of MPLS-TP linear protection as defined in
   [RFC6378].  Please refer to [RFC5920] for MPLS security issues and
   generic methods for securing traffic privacy and integrity.

6.  References

6.1.  Normative References








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   [I-D.cheng-pwe3-mpls-tp-dual-homing-protection]
              Cheng, W., Wang, L., Li, H., Liu, K., Davari, S., and J.
              Dong, "Dual-Homing Protection for MPLS Transport Profile
              (MPLS-TP) Pseudowires", draft-cheng-pwe3-mpls-tp-dual-
              homing-protection-00 (work in progress), July 2014.

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

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

   [RFC6372]  Sprecher, N. and A. Farrel, "MPLS Transport Profile (MPLS-
              TP) Survivability Framework", RFC 6372, September 2011.

   [RFC6378]  Weingarten, Y., Bryant, S., Osborne, E., Sprecher, N., and
              A. Fulignoli, "MPLS Transport Profile (MPLS-TP) Linear
              Protection", RFC 6378, October 2011.

   [RFC7271]  Ryoo, J., Gray, E., van Helvoort, H., D'Alessandro, A.,
              Cheung, T., and E. Osborne, "MPLS Transport Profile (MPLS-
              TP) Linear Protection to Match the Operational
              Expectations of Synchronous Digital Hierarchy, Optical
              Transport Network, and Ethernet Transport Network
              Operators", RFC 7271, June 2014.

   [RFC7324]  Osborne, E., "Updates to MPLS Transport Profile Linear
              Protection", RFC 7324, July 2014.

6.2.  Informative References

   [I-D.ietf-pwe3-endpoint-fast-protection]
              Shen, Y., Aggarwal, R., Henderickx, W., and Y. Jiang, "PW
              Endpoint Fast Failure Protection", draft-ietf-pwe3-
              endpoint-fast-protection-01 (work in progress), July 2014.

   [RFC5920]  Fang, L., "Security Framework for MPLS and GMPLS
              Networks", RFC 5920, July 2010.

   [RFC6718]  Muley, P., Aissaoui, M., and M. Bocci, "Pseudowire
              Redundancy", RFC 6718, August 2012.

   [RFC6870]  Muley, P. and M. Aissaoui, "Pseudowire Preferential
              Forwarding Status Bit", RFC 6870, February 2013.







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Authors' Addresses

   Weiqiang Cheng
   China Mobile
   No.32 Xuanwumen West Street
   Beijing  100053
   China

   Email: chengweiqiang@chinamobile.com


   Lei Wang
   China Mobile
   No.32 Xuanwumen West Street
   Beijing  100053
   China

   Email: Wangleiyj@chinamobile.com


   Han Li
   China Mobile
   No.32 Xuanwumen West Street
   Beijing  100053
   China

   Email: Lihan@chinamobile.com


   Kai Liu
   Huawei Technologies
   Huawei Base, Bantian, Longgang District
   Shenzhen  518129
   China

   Email: alex.liukai@huawei.com


   Shahram Davari
   Broadcom Corporation
   3151 Zanker Road
   San Jose  95134-1933
   United States

   Email: davari@broadcom.com






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   Jie Dong
   Huawei Technologies
   Huawei Campus, No. 156 Beiqing Rd.
   Beijing  100095
   China

   Email: jie.dong@huawei.com


   Alessandro D'Alessandro
   Telecom Italia
   via Reiss Romoli, 274
   Torino  10148
   Italy

   Email: alessandro.dalessandro@telecomitalia.it



































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