





Internet Engineering Task Force (IETF)                 L. Andersson, Ed.
Request for Comments: 6373                                      Ericsson
Category: Informational                                   L. Berger, Ed.
ISSN: 2070-1721                                                     LabN
                                                            L. Fang, Ed.
                                                                   Cisco
                                                           N. Bitar, Ed.
                                                                 Verizon
                                                            E. Gray, Ed.
                                                                Ericsson
                                                          September 2011


        MPLS Transport Profile (MPLS-TP) Control Plane Framework

Abstract

   The MPLS Transport Profile (MPLS-TP) supports static provisioning of
   transport paths via a Network Management System (NMS) and dynamic
   provisioning of transport paths via a control plane.  This document
   provides the framework for MPLS-TP dynamic provisioning and covers
   control-plane addressing, routing, path computation, signaling,
   traffic engineering, and path recovery.  MPLS-TP uses GMPLS as the
   control plane for MPLS-TP Label Switched Paths (LSPs).  MPLS-TP also
   uses the pseudowire (PW) control plane for pseudowires.  Management-
   plane functions are out of scope of this document.

   This document is a product of a joint Internet Engineering Task Force
   (IETF) / International Telecommunication Union Telecommunication
   Standardization Sector (ITU-T) effort to include an MPLS Transport
   Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge
   (PWE3) architectures to support the capabilities and functionalities
   of a packet transport network as defined by the ITU-T.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.






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   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6373.

Copyright Notice

   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. Scope ......................................................4
      1.2. Basic Approach .............................................4
      1.3. Reference Model ............................................6
   2. Control-Plane Requirements ......................................9
      2.1. Primary Requirements .......................................9
      2.2. Requirements Derived from the MPLS-TP Framework ...........18
      2.3. Requirements Derived from the OAM Framework ...............20
      2.4. Security Requirements .....................................25
      2.5. Identifier Requirements ...................................25
   3. Relationship of PWs and TE LSPs ................................26
   4. TE LSPs ........................................................27
      4.1. GMPLS Functions and MPLS-TP LSPs ..........................27
           4.1.1. In-Band and Out-of-Band Control ....................27
           4.1.2. Addressing .........................................29
           4.1.3. Routing ............................................29
           4.1.4. TE LSPs and Constraint-Based Path Computation ......29
           4.1.5. Signaling ..........................................30
           4.1.6. Unnumbered Links ...................................30
           4.1.7. Link Bundling ......................................30
           4.1.8. Hierarchical LSPs ..................................31
           4.1.9. LSP Recovery .......................................31
           4.1.10. Control-Plane Reference Points (E-NNI,
                   I-NNI, UNI) .......................................32
      4.2. OAM, MEP (Hierarchy), MIP Configuration and Control .......32
           4.2.1. Management-Plane Support ...........................33
      4.3. GMPLS and MPLS-TP Requirements Table ......................34



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      4.4. Anticipated MPLS-TP-Related Extensions and Definitions ....37
           4.4.1. MPLS-TE to MPLS-TP LSP Control-Plane Interworking ..37
           4.4.2. Associated Bidirectional LSPs ......................38
           4.4.3. Asymmetric Bandwidth LSPs ..........................38
           4.4.4. Recovery for P2MP LSPs .............................38
           4.4.5. Test Traffic Control and Other OAM Functions .......38
           4.4.6. Diffserv Object Usage in GMPLS .....................39
           4.4.7. Support for MPLS-TP LSP Identifiers ................39
           4.4.8. Support for MPLS-TP Maintenance Identifiers ........39
   5. Pseudowires ....................................................39
      5.1. LDP Functions and Pseudowires .............................39
           5.1.1. Management-Plane Support ...........................40
      5.2. PW Control (LDP) and MPLS-TP Requirements Table ...........40
      5.3. Anticipated MPLS-TP-Related Extensions ....................44
           5.3.1. Extensions to Support Out-of-Band PW Control .......44
           5.3.2. Support for Explicit Control of PW-to-LSP Binding ..45
           5.3.3. Support for Dynamic Transfer of PW
                  Control/Ownership ..................................45
           5.3.4. Interoperable Support for PW/LSP Resource
                  Allocation .........................................46
           5.3.5. Support for PW Protection and PW OAM
                  Configuration ......................................46
           5.3.6. Client Layer and Cross-Provider Interfaces
                  to PW Control ......................................47
      5.4. ASON Architecture Considerations ..........................47
   6. Security Considerations ........................................47
   7. Acknowledgments ................................................48
   8. References .....................................................48
      8.1. Normative References ......................................48
      8.2. Informative References ....................................51
   9. Contributing Authors ...........................................56

1.  Introduction

   The Multiprotocol Label Switching Transport Profile (MPLS-TP) is
   defined as a joint effort between the International Telecommunication
   Union (ITU) and the IETF.  The requirements for MPLS-TP are defined
   in the requirements document, see [RFC5654].  These requirements
   state that "A solution MUST be defined to support dynamic
   provisioning of MPLS-TP transport paths via a control plane".  This
   document provides the framework for such dynamic provisioning.  This
   document is a product of a joint Internet Engineering Task Force
   (IETF) / International Telecommunication Union Telecommunication
   Standardization Sector (ITU-T) effort to include an MPLS Transport
   Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge
   (PWE3) architectures to support the capabilities and functions of a
   packet transport network as defined by the ITU-T.




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1.1.  Scope

   This document covers the control-plane functions involved in
   establishing MPLS-TP Label Switched Paths (LSPs) and pseudowires
   (PWs).  The control-plane requirements for MPLS-TP are defined in the
   MPLS-TP requirements document [RFC5654].  These requirements define
   the role of the control plane in MPLS-TP.  In particular, Section 2.4
   of [RFC5654] and portions of the remainder of Section 2 of [RFC5654]
   provide specific control-plane requirements.

   The LSPs provided by MPLS-TP are used as a server layer for IP, MPLS,
   and PWs, as well as other tunneled MPLS-TP LSPs.  The PWs are used to
   carry client signals other than IP or MPLS.  The relationship between
   PWs and MPLS-TP LSPs is exactly the same as between PWs and MPLS LSPs
   in an MPLS Packet Switched Network (PSN).  The PW encapsulation over
   MPLS-TP LSPs used in MPLS-TP networks is also the same as for PWs
   over MPLS in an MPLS network.  MPLS-TP also defines protection and
   restoration (or, collectively, recovery) functions; see [RFC5654] and
   [RFC4427].  The MPLS-TP control plane provides methods to establish,
   remove, and control MPLS-TP LSPs and PWs.  This includes control of
   Operations, Administration, and Maintenance (OAM), data-plane, and
   recovery functions.

   A general framework for MPLS-TP has been defined in [RFC5921], and a
   survivability framework for MPLS-TP has been defined in [RFC6372].
   These documents scope the approaches and protocols that are the
   foundation of MPLS-TP.  Notably, Section 3.5 of [RFC5921] scopes the
   IETF protocols that serve as the foundation of the MPLS-TP control
   plane.  The PW control plane is based on the existing PW control
   plane (see [RFC4447]) and the PWE3 architecture (see [RFC3985]).  The
   LSP control plane is based on GMPLS (see [RFC3945]), which is built
   on MPLS Traffic Engineering (TE) and its numerous extensions.
   [RFC6372] focuses on the recovery functions that must be supported
   within MPLS-TP.  It does not specify which control-plane mechanisms
   are to be used.

   The remainder of this document discusses the impact of the MPLS-TP
   requirements on the GMPLS signaling and routing protocols that are
   used to control MPLS-TP LSPs, and on the control of PWs as specified
   in [RFC4447], [RFC6073], and [MS-PW-DYNAMIC].

1.2.  Basic Approach

   The basic approach taken in defining the MPLS-TP control-plane
   framework includes the following:

      1) MPLS technology as defined by the IETF is the foundation for
         the MPLS Transport Profile.



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      2) The data plane for MPLS-TP is a standard MPLS data plane
         [RFC3031] as profiled in [RFC5960].

      3) MPLS PWs are used by MPLS-TP including the use of targeted
         Label Distribution Protocol (LDP) as the foundation for PW
         signaling [RFC4447].  This also includes the use of Open
         Shortest Path First with Traffic Engineering (OSPF-TE),
         Intermediate System to Intermediate System (IS-IS) with Traffic
         Engineering (ISIS-TE), or Multiprotocol Border Gateway Protocol
         (MP-BGP) as they apply for Multi-Segment Pseudowire (MS-PW)
         routing.  However, the PW can be encapsulated over an MPLS-TP
         LSP (established using methods and procedures for MPLS-TP LSP
         establishment) in addition to the presently defined methods of
         carrying PWs over LSP-based PSNs.  That is, the MPLS-TP domain
         is a PSN from a PWE3 architecture perspective [RFC3985].

      4) The MPLS-TP LSP control plane builds on the GMPLS control plane
         as defined by the IETF for transport LSPs.  The protocols
         within scope are Resource Reservation Protocol with Traffic
         Engineering (RSVP-TE) [RFC3473], OSPF-TE [RFC4203] [RFC5392],
         and ISIS-TE [RFC5307] [RFC5316].  Automatically Switched
         Optical Network (ASON) signaling and routing requirements in
         the context of GMPLS can be found in [RFC4139] and [RFC4258].

      5) Existing IETF MPLS and GMPLS RFCs and evolving Working Group
         Internet-Drafts should be reused wherever possible.

      6) If needed, extensions for the MPLS-TP control plane should
         first be based on the existing and evolving IETF work, and
         secondly be based on work by other standard bodies only when
         IETF decides that the work is out of the IETF's scope.  New
         extensions may be defined otherwise.

      7) Extensions to the control plane may be required in order to
         fully automate functions related to MPLS-TP LSPs and PWs.

      8) Control-plane software upgrades to existing equipment are
         acceptable and expected.

      9) It is permissible for functions present in the GMPLS and PW
         control planes to not be used in MPLS-TP networks.

     10) One possible use of the control plane is to configure, enable,
         and generally control OAM functionality.  This will require
         extensions to existing control-plane specifications that will
         be usable in MPLS-TP as well as MPLS networks.





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     11) The foundation for MPLS-TP control-plane requirements is
         primarily found in Section 2.4 of [RFC5654] and relevant
         portions of the remainder of Section 2 of [RFC5654].

1.3.  Reference Model

   The control-plane reference model is based on the general MPLS-TP
   reference model as defined in the MPLS-TP framework [RFC5921] and
   further refined in [RFC6215] on the MPLS-TP User-to-Network and
   Network-to-Network Interfaces (UNI and NNI, respectively).  Per the
   MPLS-TP framework [RFC5921], the MPLS-TP control plane is based on
   GMPLS with RSVP-TE for LSP signaling and targeted LDP for PW
   signaling.  In both cases, OSPF-TE or ISIS-TE with GMPLS extensions
   is used for dynamic routing within an MPLS-TP domain.

   Note that in this context, "targeted LDP" (or T-LDP) means LDP as
   defined in RFC 5036, using Targeted Hello messages.  See Section
   2.4.2 ("Extended Discovery Mechanism") of [RFC5036].  Use of the
   extended discovery mechanism is specified in Section 5 ("LDP") of
   [RFC4447].

   From a service perspective, MPLS-TP client services may be supported
   via both PWs and LSPs.  PW client interfaces, or adaptations, are
   defined on an interface-technology basis, e.g., Ethernet over PW
   [RFC4448].  In the context of MPLS-TP LSP, the client interface is
   provided at the network layer and may be controlled via a GMPLS-based
   UNI, see [RFC4208], or statically provisioned.  As discussed in
   [RFC5921] and [RFC6215], MPLS-TP also presumes an NNI reference
   point.

   The MPLS-TP end-to-end control-plane reference model is shown in
   Figure 1.  The figure shows the control-plane protocols used by MPLS-
   TP, as well as the UNI and NNI reference points, in the case of a
   Single-Segment PW supported by an end-to-end LSP without any
   hierarchical LSPs.  (The MS-PW case is not shown.)  Each service
   provider node's participation in routing and signaling (both GMPLS
   RSVP-TE and PW LDP) is represented.  Note that only the service end
   points participate in PW LDP signaling, while all service provider
   nodes participate in GMPLS TE LSP routing and signaling.












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       |< ---- client signal (e.g., IP / MPLS / L2) -------- >|
         |< --------- SP1 ---------- >|< ------- SP2 ----- >|
           |< ---------- MPLS-TP End-to-End PW --------- >|
             |< -------- MPLS-TP End-to-End LSP ------ >|

   +---+   +---+  +---+  +---+  +---+   +---+  +---+  +---+   +---+
   |CE1|-|-|PE1|--|P1 |--|P2 |--|PE2|-|-|PEa|--|Pa |--|PEb|-|-|CE2|
   +---+   +---+  +---+  +---+  +---+   +---+  +---+  +---+   +---+
        UNI                          NNI                   UNI
   GMPLS
    TE-RTG,  |<-----|------|------|-------|------|----->|
    & RSVP-TE

   PW LDP   |< ---------------------------------------- >|

    Figure 1.  End-to-End MPLS-TP Control-Plane Reference Model

     Legend:
          CE:            Customer Edge
          Client signal: defined in MPLS-TP Requirements
          L2:            Any layer 2 signal that may be carried
                         over a PW, e.g., Ethernet
          NNI:           Network-to-Network Interface
          P:             Provider
          PE:            Provider Edge
          SP:            Service Provider
          TE-RTG:        GMPLS OSPF-TE or ISIS-TE
          UNI:           User-to-Network Interface

     Note: The MS-PW case is not shown.

   Figure 2 adds three hierarchical LSP segments, labeled as "H-LSPs".
   These segments are present to support scaling, OAM, and Maintenance
   Entity Group End Points (MEPs), see [RFC6371], within each provider
   domain and across the inter-provider NNI.  (H-LSPs are used to
   implement Sub-Path Maintenance Elements (SPMEs) as defined in
   [RFC5921].)  The MEPs are used to collect performance information,
   support diagnostic and fault management functions, and support OAM
   triggered survivability schemes as discussed in [RFC6372].  Each
   H-LSP may be protected or restored using any of the schemes discussed
   in [RFC6372].  End-to-end monitoring is supported via MEPs at the
   end-to-end LSP and PW end points.  Note that segment MEPs may be co-
   located with MIPs of the next higher-layer (e.g., end-to-end) LSPs.
   (The MS-PW case is not shown.)







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       |< ------- client signal (e.g., IP / MPLS / L2) ----- >|
         |< -------- SP1 ----------- >|< ------- SP2 ----- >|
           |< ----------- MPLS-TP End-to-End PW -------- >|
             |< ------- MPLS-TP End-to-End LSP ------- >|
             |< -- H-LSP1 ---- >|<-H-LSP2->|<- H-LSP3 ->|

   +---+   +---+  +---+  +---+  +---+   +---+  +---+  +---+   +---+
   |CE1|-|-|PE1|--|P1 |--|P2 |--|PE2|-|-|PEa|--|Pa |--|PEb|-|-|CE2|
   +---+   +---+  +---+  +---+  +---+   +---+  +---+  +---+   +---+
        UNI                          NNI                   UNI
           .....                                      .....
   End2end |MEP|--------------------------------------|MEP|
   PW OAM  '''''                                      '''''
           .....                .....   .....         .....
   End2end |MEP|----------------|MIP|---|MIP|---------|MEP|
   LSP OAM '''''                '''''   '''''         '''''
           ..... ..... ..... ......... ......... ..... .....
   Segment |MEP|-|MIP|-|MIP|-|MEP|MEP|-|MEP|MEP|-|MIP|-|MEP|
   LSP OAM ''''' ''''' ''''' ''''''''' ''''''''' ''''' '''''

   H-LSP GMPLS
    TE-RTG   |<-----|------|----->||<---->||<-----|----->|
    &RSVP-TE (within an MPLS-TP network)

   E2E GMPLS
    TE-RTG   |< ------------------|--------|------------>|
    &RSVP-TE

   PW LDP    |< ---------------------------------------- >|

     Figure 2.  MPLS-TP Control-Plane Reference Model with OAM

     Legend:
          CE:            Customer Edge
          Client signal: defined in MPLS-TP Requirements
          E2E:           End-to-End
          L2:            Any layer 2 signal that may be carried
                         over a PW, e.g., Ethernet
          H-LSP:         Hierarchical LSP
          MEP:           Maintenance Entity Group End Point
          MIP:           Maintenance Entity Group Intermediate Point
          NNI:           Network-to-Network Interface
          P:             Provider
          PE:            Provider Edge
          SP:            Service Provider
          TE-RTG:        GMPLS OSPF-TE or ISIS-TE

     Note: The MS-PW case is not shown.



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   While not shown in the figures above, the MPLS-TP control plane must
   support the addressing separation and independence between the data,
   control, and management planes.  Address separation between the
   planes is already included in GMPLS.  Such separation is also already
   included in LDP as LDP session end point addresses are never
   automatically associated with forwarding.

2.  Control-Plane Requirements

   The requirements for the MPLS-TP control plane are derived from the
   MPLS-TP requirements and framework documents, specifically [RFC5654],
   [RFC5921], [RFC5860], [RFC6371], and [RFC6372].  The requirements are
   summarized in this section, but do not replace those documents.  If
   there are differences between this section and those documents, those
   documents shall be considered authoritative.

2.1.  Primary Requirements

   These requirements are based on Section 2 of [RFC5654]:

      1. Any new functionality that is defined to fulfill the
         requirements for MPLS-TP must be agreed within the IETF through
         the IETF consensus process as per [RFC4929] and Section 1,
         paragraph 15 of [RFC5654].

      2. The MPLS-TP control-plane design should as far as reasonably
         possible reuse existing MPLS standards ([RFC5654], requirement
         2).

      3. The MPLS-TP control plane must be able to interoperate with
         existing IETF MPLS and PWE3 control planes where appropriate
         ([RFC5654], requirement 3).

      4. The MPLS-TP control plane must be sufficiently well-defined to
         ensure that the interworking between equipment supplied by
         multiple vendors will be possible both within a single domain
         and between domains ([RFC5654], requirement 4).

      5. The MPLS-TP control plane must support a connection-oriented
         packet switching model with traffic engineering capabilities
         that allow deterministic control of the use of network
         resources ([RFC5654], requirement 5).

      6. The MPLS-TP control plane must support traffic-engineered
         point-to-point (P2P) and point-to-multipoint (P2MP) transport
         paths ([RFC5654], requirement 6).





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      7. The MPLS-TP control plane must support unidirectional,
         associated bidirectional and co-routed bidirectional point-to-
         point transport paths ([RFC5654], requirement 7).

      8. The MPLS-TP control plane must support unidirectional point-to-
         multipoint transport paths ([RFC5654], requirement 8).

      9. The MPLS-TP control plane must enable all nodes (i.e., ingress,
         egress, and intermediate) to be aware about the pairing
         relationship of the forward and the backward directions
         belonging to the same co-routed bidirectional transport path
         ([RFC5654], requirement 10).

     10. The MPLS-TP control plane must enable edge nodes (i.e., ingress
         and egress) to be aware of the pairing relationship of the
         forward and the backward directions belonging to the same
         associated bidirectional transport path ([RFC5654], requirement
         11).

     11. The MPLS-TP control plane should enable common transit nodes to
         be aware of the pairing relationship of the forward and the
         backward directions belonging to the same associated
         bidirectional transport path ([RFC5654], requirement 12).

     12. The MPLS-TP control plane must support bidirectional transport
         paths with symmetric bandwidth requirements, i.e., the amount
         of reserved bandwidth is the same in the forward and backward
         directions ([RFC5654], requirement 13).

     13. The MPLS-TP control plane must support bidirectional transport
         paths with asymmetric bandwidth requirements, i.e., the amount
         of reserved bandwidth differs in the forward and backward
         directions ([RFC5654], requirement 14).

     14. The MPLS-TP control plane must support the logical separation
         of the control plane from the management and data planes
         ([RFC5654], requirement 15).  Note that this implies that the
         addresses used in the control plane are independent from the
         addresses used in the management and data planes.

     15. The MPLS-TP control plane must support the physical separation
         of the control plane from the management and data plane, and no
         assumptions should be made about the state of the data-plane
         channels from information about the control- or management-
         plane channels when they are running out-of-band ([RFC5654],
         requirement 16).





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     16. A control plane must be defined to support dynamic provisioning
         and restoration of MPLS-TP transport paths, but its use is a
         network operator's choice ([RFC5654], requirement 18).

     17. The presence of a control plane must not be required for static
         provisioning of MPLS-TP transport paths ([RFC5654], requirement
         19).

     18. The MPLS-TP control plane must permit the coexistence of
         statically and dynamically provisioned/managed MPLS-TP
         transport paths within the same layer network or domain
         ([RFC5654], requirement 20).

     19. The MPLS-TP control plane should be operable in a way that is
         similar to the way the control plane operates in other
         transport-layer technologies ([RFC5654], requirement 21).

     20. The MPLS-TP control plane must avoid or minimize traffic impact
         (e.g., packet delay, reordering, and loss) during network
         reconfiguration ([RFC5654], requirement 24).

     21. The MPLS-TP control plane must work across multiple homogeneous
         domains ([RFC5654], requirement 25), i.e., all domains use the
         same MPLS-TP control plane.

     22. The MPLS-TP control plane should work across multiple non-
         homogeneous domains ([RFC5654], requirement 26), i.e., some
         domains use the same control plane and other domains use static
         provisioning at the domain boundary.

     23. The MPLS-TP control plane must not dictate any particular
         physical or logical topology ([RFC5654], requirement 27).

     24. The MPLS-TP control plane must include support of ring
         topologies that may be deployed with arbitrary interconnection
         and support of rings of at least 16 nodes ([RFC5654],
         requirements 27.A, 27.B, and 27.C).

     25. The MPLS-TP control plane must scale gracefully to support a
         large number of transport paths, nodes, and links.  That is, it
         must be able to scale at least as well as control planes in
         existing transport technologies with growing and increasingly
         complex network topologies as well as with increasing bandwidth
         demands, number of customers, and number of services
         ([RFC5654], requirements 53 and 28).

     26. The MPLS-TP control plane should not provision transport paths
         that contain forwarding loops ([RFC5654], requirement 29).



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     27. The MPLS-TP control plane must support multiple client layers
         (e.g., MPLS-TP, IP, MPLS, Ethernet, ATM, Frame Relay, etc.)
         ([RFC5654], requirement 30).

     28. The MPLS-TP control plane must provide a generic and extensible
         solution to support the transport of MPLS-TP transport paths
         over one or more server-layer networks (such as MPLS-TP,
         Ethernet, Synchronous Optical Network / Synchronous Digital
         Hierarchy (SONET/SDH), Optical Transport Network (OTN), etc.).
         Requirements for bandwidth management within a server-layer
         network are outside the scope of this document ([RFC5654],
         requirement 31).

     29. In an environment where an MPLS-TP layer network is supporting
         a client-layer network, and the MPLS-TP layer network is
         supported by a server-layer network, then the control-plane
         operation of the MPLS-TP layer network must be possible without
         any dependencies on the server or client-layer network
         ([RFC5654], requirement 32).

     30. The MPLS-TP control plane must allow for the transport of a
         client MPLS or MPLS-TP layer network over a server MPLS or
         MPLS-TP layer network ([RFC5654], requirement 33).

     31. The MPLS-TP control plane must allow the autonomous operation
         of the layers of a multi-layer network that includes an MPLS-TP
         layer ([RFC5654], requirement 34).

     32. The MPLS-TP control plane must allow the hiding of MPLS-TP
         layer network addressing and other information (e.g., topology)
         from client-layer networks.  However, it should be possible, at
         the option of the operator, to leak a limited amount of
         summarized information, such as Shared Risk Link Groups (SRLGs)
         or reachability, between layers ([RFC5654], requirement 35).

     33. The MPLS-TP control plane must allow for the identification of
         a transport path on each link within and at the destination
         (egress) of the transport network ([RFC5654], requirements 38
         and 39).

     34. The MPLS-TP control plane must allow for the use of P2MP server
         (sub-)layer capabilities as well as P2P server (sub-)layer
         capabilities when supporting P2MP MPLS-TP transport paths
         ([RFC5654], requirement 40).

     35. The MPLS-TP control plane must be extensible in order to
         accommodate new types of client-layer networks and services
         ([RFC5654], requirement 41).



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     36. The MPLS-TP control plane should support the reserved bandwidth
         associated with a transport path to be increased without
         impacting the existing traffic on that transport path, provided
         enough resources are available ([RFC5654], requirement 42)).

     37. The MPLS-TP control plane should support the reserved bandwidth
         of a transport path being decreased without impacting the
         existing traffic on that transport path, provided that the
         level of existing traffic is smaller than the reserved
         bandwidth following the decrease ([RFC5654], requirement 43).

     38. The control plane for MPLS-TP must fit within the ASON
         (control-plane) architecture.  The ITU-T has defined an
         architecture for ASONs in G.8080 [ITU.G8080.2006] and G.8080
         Amendment 1 [ITU.G8080.2008].  An interpretation of the ASON
         signaling and routing requirements in the context of GMPLS can
         be found in [RFC4139], [RFC4258], and Section 2.4, paragraphs 2
         and 3 of [RFC5654].

     39. The MPLS-TP control plane must support control-plane topology
         and data-plane topology independence ([RFC5654], requirement
         47).

     40. A failure of the MPLS-TP control plane must not interfere with
         the delivery of service or recovery of established transport
         paths ([RFC5654], requirement 47).

     41. The MPLS-TP control plane must be able to operate independent
         of any particular client- or server-layer control plane
         ([RFC5654], requirement 48).

     42. The MPLS-TP control plane should support, but not require, an
         integrated control plane encompassing MPLS-TP together with its
         server- and client-layer networks when these layer networks
         belong to the same administrative domain ([RFC5654],
         requirement 49).

     43. The MPLS-TP control plane must support configuration of
         protection functions and any associated maintenance (OAM)
         functions ([RFC5654], requirements 50 and 7).

     44. 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 ([RFC5654],
         requirement 51).





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     45. The MPLS-TP control plane must be capable of restarting and
         relearning its previous state without impacting forwarding
         ([RFC5654], requirement 54).

     46. The MPLS-TP control plane must provide a mechanism for dynamic
         ownership transfer of the control of MPLS-TP transport paths
         from the management plane to the control plane and vice versa.
         The number of reconfigurations required in the data plane must
         be minimized; preferably no data-plane reconfiguration will be
         required ([RFC5654], requirement 55).  Note, such transfers
         cover all transport path control functions including control of
         recovery and OAM.

     47. The MPLS-TP control plane must support protection and
         restoration mechanisms, i.e., recovery ([RFC5654], requirement
         52).

         Note that the MPLS-TP survivability framework document
         [RFC6372] provides additional useful information related to
         recovery.

     48. The MPLS-TP control-plane mechanisms should be identical (or as
         similar as possible) to those already used in existing
         transport networks to simplify implementation and operations.
         However, this must not override any other requirement
         ([RFC5654], requirement 56 A).

     49. The MPLS-TP control-plane mechanisms used for P2P and P2MP
         recovery should be identical to simplify implementation and
         operation.  However, this must not override any other
         requirement ([RFC5654], requirement 56 B).

     50. The MPLS-TP control plane must support recovery mechanisms that
         are applicable at various levels throughout the network
         including support for link, transport path, segment,
         concatenated segment, and end-to-end recovery ([RFC5654],
         requirement 57).

     51. The MPLS-TP control plane must support recovery paths that meet
         the Service Level Agreement (SLA) protection objectives of the
         service ([RFC5654], requirement 58).  These include:

         a. Guarantee 50-ms recovery times from the moment of fault
            detection in networks with spans less than 1200 km.

         b. Protection of 100% of the traffic on the protected path.

         c. Recovery must meet SLA requirements over multiple domains.



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     52. The MPLS-TP control plane should support per-transport-path
         recovery objectives ([RFC5654], requirement 59).

     53. The MPLS-TP control plane must support recovery mechanisms that
         are applicable to any topology ([RFC5654], requirement 60).

     54. The MPLS-TP control plane must operate in synergy with
         (including coordination of timing/timer settings) the recovery
         mechanisms present in any client or server transport networks
         (for example, Ethernet, SDH, OTN, Wavelength Division
         Multiplexing (WDM)) to avoid race conditions between the layers
         ([RFC5654], requirement 61).

     55. The MPLS-TP control plane must support recovery and reversion
         mechanisms that prevent frequent operation of recovery in the
         event of an intermittent defect ([RFC5654], requirement 62).

     56. The MPLS-TP control plane must support revertive and non-
         revertive protection behavior ([RFC5654], requirement 64).

     57. The MPLS-TP control plane must support 1+1 bidirectional
         protection for P2P transport paths ([RFC5654], requirement 65
         A).

     58. The MPLS-TP control plane must support 1+1 unidirectional
         protection for P2P transport paths ([RFC5654], requirement 65
         B).

     59. The MPLS-TP control plane must support 1+1 unidirectional
         protection for P2MP transport paths ([RFC5654], requirement 65
         C).

     60. The MPLS-TP control plane must support the ability to share
         protection resources amongst a number of transport paths
         ([RFC5654], requirement 66).

     61. The MPLS-TP control plane must support 1:n bidirectional
         protection for P2P transport paths.  Bidirectional 1:n
         protection should be the default for 1:n protection ([RFC5654],
         requirement 67 A).

     62. The MPLS-TP control plane must support 1:n unidirectional
         protection for P2MP transport paths ([RFC5654], requirement 67
         B).

     63. The MPLS-TP control plane may support 1:n unidirectional
         protection for P2P transport paths ([RFC5654], requirement 65
         C).



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     64. The MPLS-TP control plane may support the control of extra-
         traffic type traffic ([RFC5654], note after requirement 67).

     65. The MPLS-TP control plane should support 1:n (including 1:1)
         shared mesh recovery ([RFC5654], requirement 68).

     66. The MPLS-TP control plane must support sharing of protection
         resources such that protection paths that are known not to be
         required concurrently can share the same resources ([RFC5654],
         requirement 69).

     67. The MPLS-TP control plane must support the sharing of resources
         between a restoration transport path and the transport path
         being replaced ([RFC5654], requirement 70).

     68. The MPLS-TP control plane must support restoration priority so
         that an implementation can determine the order in which
         transport paths should be restored ([RFC5654], requirement 71).

     69. The MPLS-TP control plane must support preemption priority in
         order to allow restoration to displace other transport paths in
         the event of resource constraints ([RFC5654], requirements 72
         and 86).

     70. The MPLS-TP control plane must support revertive and non-
         revertive restoration behavior ([RFC5654], requirement 73).

     71. The MPLS-TP control plane must support recovery being triggered
         by physical (lower) layer fault indications ([RFC5654],
         requirement 74).

     72. The MPLS-TP control plane must support recovery being triggered
         by OAM ([RFC5654], requirement 75).

     73. The MPLS-TP control plane must support management-plane
         recovery triggers (e.g., forced switch, etc.) ([RFC5654],
         requirement 76).

     74. The MPLS-TP control plane must support the differentiation of
         administrative recovery actions from recovery actions initiated
         by other triggers ([RFC5654], requirement 77).

     75. The MPLS-TP control plane should support control-plane
         restoration triggers (e.g., forced switch, etc.) ([RFC5654],
         requirement 78).






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     76. The MPLS-TP control plane must support priority logic to
         negotiate and accommodate coexisting requests (i.e., multiple
         requests) for protection switching (e.g., administrative
         requests and requests due to link/node failures) ([RFC5654],
         requirement 79).

     77. The MPLS-TP control plane must support the association of
         protection paths and working paths (sometimes known as
         protection groups) ([RFC5654], requirement 80).

     78. The MPLS-TP control plane must support pre-calculation of
         recovery paths ([RFC5654], requirement 81).

     79. The MPLS-TP control plane must support pre-provisioning of
         recovery paths ([RFC5654], requirement 82).

     80. The MPLS-TP control plane must support the external commands
         defined in [RFC4427].  External controls overruled by higher
         priority requests (e.g., administrative requests and requests
         due to link/node failures) or unable to be signaled to the
         remote end (e.g., because of a protection state coordination
         fail) must be ignored/dropped ([RFC5654], requirement 83).

     81. The MPLS-TP control plane must permit the testing and
         validation of the integrity of the protection/recovery
         transport path ([RFC5654], requirement 84 A).

     82. The MPLS-TP control plane must permit the testing and
         validation of protection/restoration mechanisms without
         triggering the actual protection/restoration ([RFC5654],
         requirement 84 B).

     83. The MPLS-TP control plane must permit the testing and
         validation of protection/restoration mechanisms while the
         working path is in service ([RFC5654], requirement 84 C).

     84. The MPLS-TP control plane must permit the testing and
         validation of protection/restoration mechanisms while the
         working path is out of service ([RFC5654], requirement 84 D).

     85. The MPLS-TP control plane must support the establishment and
         maintenance of all recovery entities and functions ([RFC5654],
         requirement 89 A).

     86. The MPLS-TP control plane must support signaling of recovery
         administrative control ([RFC5654], requirement 89 B).





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     87. The MPLS-TP control plane must support protection state
         coordination.  Since control-plane network topology is
         independent from the data-plane network topology, the
         protection state coordination supported by the MPLS-TP control
         plane may run on resources different than the data-plane
         resources handled within the recovery mechanism (e.g., backup)
         ([RFC5654], requirement 89 C).

     88. When present, the MPLS-TP control plane must support recovery
         mechanisms that are optimized for specific network topologies.
         These mechanisms must be interoperable with the mechanisms
         defined for arbitrary topology (mesh) networks to enable
         protection of end-to-end transport paths ([RFC5654],
         requirement 91).

     89. When present, the MPLS-TP control plane must support the
         control of ring-topology-specific recovery mechanisms
         ([RFC5654], Section 2.5.6.1).

     90. The MPLS-TP control plane must include support for
         differentiated services and different traffic types with
         traffic class separation associated with different traffic
         ([RFC5654], requirement 110).

     91. The MPLS-TP control plane must support the provisioning of
         services that provide guaranteed Service Level Specifications
         (SLSs), with support for hard ([RFC3209] style) and relative
         ([RFC3270] style) end-to-end bandwidth guarantees ([RFC5654],
         requirement 111).

     92. The MPLS-TP control plane must support the provisioning of
         services that are sensitive to jitter and delay ([RFC5654],
         requirement 112).

2.2.  Requirements Derived from the MPLS-TP Framework

   The following additional requirements are based on [RFC5921],
   [TP-P2MP-FWK], and [RFC5960]:

     93. Per-packet Equal Cost Multi-Path (ECMP) load balancing is
         currently outside the scope of MPLS-TP ([RFC5960], Section
         3.1.1, paragraph 6).

     94. Penultimate Hop Popping (PHP) must be disabled on MPLS-TP LSPs
         by default ([RFC5960], Section 3.1.1, paragraph 7).






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     95. The MPLS-TP control plane must support both E-LSP (Explicitly
         TC-encoded-PSC LSP) and L-LSP (Label-Only-Inferred-PSC LSP)
         MPLS Diffserv modes as specified in [RFC3270], [RFC5462], and
         Section 3.3.2, paragraph 12 of [RFC5960].

     96. Both Single-Segment PWs (see [RFC3985]) and Multi-Segment PWs
         (see [RFC5659]) shall be supported by the MPLS-TP control
         plane.  MPLS-TP shall use the definition of Multi-Segment PWs
         as defined by the IETF ([RFC5921], Section 3.4.4).

     97. The MPLS-TP control plane must support the control of PWs and
         their associated labels ([RFC5921], Section 3.4.4).

     98. The MPLS-TP control plane must support network-layer clients,
         i.e., clients whose traffic is transported over an MPLS-TP
         network without the use of PWs ([RFC5921], Section 3.4.5).

         a. The MPLS-TP control plane must support the use of network-
            layer protocol-specific LSPs and labels ([RFC5921], Section
            3.4.5).

         b. The MPLS-TP control plane must support the use of a client-
            service-specific LSPs and labels ([RFC5921], Section 3.4.5).

     99. The MPLS-TP control plane for LSPs must be based on the GMPLS
         control plane.  More specifically, GMPLS RSVP-TE [RFC3473] and
         related extensions are used for LSP signaling, and GMPLS OSPF-
         TE [RFC5392] and ISIS-TE [RFC5316] are used for routing
         ([RFC5921], Section 3.9).

    100. The MPLS-TP control plane for PWs must be based on the MPLS
         control plane for PWs, and more specifically, targeted LDP (T-
         LDP) [RFC4447] is used for PW signaling ([RFC5921], Section
         3.9, paragraph 5).

    101. The MPLS-TP control plane must ensure its own survivability and
         be able to recover gracefully from failures and degradations.
         These include graceful restart and hot redundant configurations
         ([RFC5921], Section 3.9, paragraph 16).

    102. The MPLS-TP control plane must support linear, ring, and meshed
         protection schemes ([RFC5921], Section 3.12, paragraph 3).

    103. The MPLS-TP control plane must support the control of SPMEs
         (hierarchical LSPs) for new or existing end-to-end LSPs
         ([RFC5921], Section 3.12, paragraph 7).





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2.3.  Requirements Derived from the OAM Framework

   The following additional requirements are based on [RFC5860] and
   [RFC6371]:

    104. The MPLS-TP control plane must support the capability to
         enable/disable OAM functions as part of service establishment
         ([RFC5860], Section 2.1.6, paragraph 1.  Note that OAM
         functions are applicable regardless of the label stack depth
         (i.e., level of LSP hierarchy or PW) ([RFC5860], Section 2.1.1,
         paragraph 3).

    105. The MPLS-TP control plane must support the capability to
         enable/disable OAM functions after service establishment.  In
         such cases, the customer must not perceive service degradation
         as a result of OAM enabling/disabling ([RFC5860], Section
         2.1.6, paragraphs 1 and 2).

    106. The MPLS-TP control plane must support dynamic control of any
         of the existing IP/MPLS and PW OAM protocols, e.g., LSP-Ping
         [RFC4379], MPLS-BFD [RFC5884], VCCV [RFC5085], and VCCV-BFD
         [RFC5885] ([RFC5860], Section 2.1.4, paragraph 2).

    107. The MPLS-TP control plane must allow for the ability to support
         experimental OAM functions.  These functions must be disabled
         by default ([RFC5860], Section 2.2, paragraph 2).

    108. The MPLS-TP control plane must support the choice of which (if
         any) OAM function(s) to use and to which PW, LSP or Section it
         applies ([RFC5860], Section 2.2, paragraph 3).

    109. The MPLS-TP control plane must allow (e.g., enable/disable)
         mechanisms that support the localization of faults and the
         notification of appropriate nodes ([RFC5860], Section 2.2.1,
         paragraph 1).

    110. The MPLS-TP control plane may support mechanisms that permit
         the service provider to be informed of a fault or defect
         affecting the service(s) it provides, even if the fault or
         defect is located outside of his domain ([RFC5860], Section
         2.2.1, paragraph 2).

    111. Information exchange between various nodes involved in the
         MPLS-TP control plane should be reliable such that, for
         example, defects or faults are properly detected or that state
         changes are effectively known by the appropriate nodes
         ([RFC5860], Section 2.2.1, paragraph 3).




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    112. The MPLS-TP control plane must provide functionality to control
         an end point's ability to monitor the liveness of a PW, LSP, or
         Section ([RFC5860], Section 2.2.2, paragraph 1).

    113. The MPLS-TP control plane must provide functionality to control
         an end point's ability to determine whether or not it is
         connected to specific end point(s) by means of the expected PW,
         LSP, or Section ([RFC5860], Section 2.2.3, paragraph 1).

         a. The MPLS-TP control plane must provide mechanisms to control
            an end point's ability to perform this function proactively
            ([RFC5860], Section 2.2.3, paragraph 2).

         b. The MPLS-TP control plane must provide mechanisms to control
            an end point's ability to perform this function on-demand
            ([RFC5860], Section 2.2.3, paragraph 3).

    114. The MPLS-TP control plane must provide functionality to control
         diagnostic testing on a PW, LSP or Section ([RFC5860], Section
         2.2.5, paragraph 1).

         a. The MPLS-TP control plane must provide mechanisms to control
            the performance of this function on-demand ([RFC5860],
            Section 2.2.5, paragraph 2).

    115. The MPLS-TP control plane must provide functionality to enable
         an end point to discover the Intermediate Point(s) (if any) and
         end point(s) along a PW, LSP, or Section, and more generally to
         trace (record) the route of a PW, LSP, or Section ([RFC5860],
         Section 2.2.4, paragraph 1).

         a. The MPLS-TP control plane must provide mechanisms to control
            the performance of this function on-demand ([RFC5860],
            Section 2.2.4, paragraph 2).

    116. The MPLS-TP control plane must provide functionality to enable
         an end point of a PW, LSP, or Section to instruct its
         associated end point(s) to lock the PW, LSP, or Section
         ([RFC5860], Section 2.2.6, paragraph 1).

         a. The MPLS-TP control plane must provide mechanisms to control
            the performance of this function on-demand ([RFC5860],
            Section 2.2.6, paragraph 2).








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    117. The MPLS-TP control plane must provide functionality to enable
         an Intermediate Point of a PW or LSP to report, to an end point
         of that same PW or LSP, a lock condition indirectly affecting
         that PW or LSP ([RFC5860], Section 2.2.7, paragraph 1).

         a. The MPLS-TP control plane must provide mechanisms to control
            the performance of this function proactively ([RFC5860],
            Section 2.2.7, paragraph 2).

    118. The MPLS-TP control plane must provide functionality to enable
         an Intermediate Point of a PW or LSP to report, to an end point
         of that same PW or LSP, a fault or defect condition affecting
         that PW or LSP ([RFC5860], Section 2.2.8, paragraph 1).

         a. The MPLS-TP control plane must provide mechanisms to control
            the performance of this function proactively ([RFC5860],
            Section 2.2.8, paragraph 2).

    119. The MPLS-TP control plane must provide functionality to enable
         an end point to report, to its associated end point, a fault or
         defect condition that it detects on a PW, LSP, or Section for
         which they are the end points ([RFC5860], Section 2.2.9,
         paragraph 1).

         a. The MPLS-TP control plane must provide mechanisms to control
            the performance of this function proactively ([RFC5860],
            Section 2.2.9, paragraph 2).

    120. The MPLS-TP control plane must provide functionality to enable
         the propagation, across an MPLS-TP network, of information
         pertaining to a client defect or fault condition detected at an
         end point of a PW or LSP, if the client-layer mechanisms do not
         provide an alarm notification/propagation mechanism ([RFC5860],
         Section 2.2.10, paragraph 1).

         a. The MPLS-TP control plane must provide mechanisms to control
            the performance of this function proactively ([RFC5860],
            Section 2.2.10, paragraph 2).

    121. The MPLS-TP control plane must provide functionality to enable
         the control of quantification of packet loss ratio over a PW,
         LSP, or Section ([RFC5860], Section 2.2.11, paragraph 1).

         a. The MPLS-TP control plane must provide mechanisms to control
            the performance of this function proactively and on-demand
            ([RFC5860], Section 2.2.11, paragraph 4).





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    122. The MPLS-TP control plane must provide functionality to control
         the quantification and reporting of the one-way, and if
         appropriate, the two-way, delay of a PW, LSP, or Section
         ([RFC5860], Section 2.2.12, paragraph 1).

         a. The MPLS-TP control plane must provide mechanisms to control
            the performance of this function proactively and on-demand
            ([RFC5860], Section 2.2.12, paragraph 6).

    123. The MPLS-TP control plane must support the configuration of OAM
         functional components that include Maintenance Entities (MEs)
         and Maintenance Entity Groups (MEGs) as instantiated in MEPs,
         MIPs, and SPMEs ([RFC6371], Section 3.6).

    124. For dynamically established transport paths, the control plane
         must support the configuration of OAM operations ([RFC6371],
         Section 5).

         a. The MPLS-TP control plane must provide mechanisms to
            configure proactive monitoring for a MEG at, or after,
            transport path creation time.

         b. The MPLS-TP control plane must provide mechanisms to
            configure the operational characteristics of in-band
            measurement transactions (e.g., Connectivity Verification
            (CV), Loss Measurement (LM), etc.) at MEPs (associated with
            a transport path).

         c. The MPLS-TP control plane may provide mechanisms to
            configure server-layer event reporting by intermediate
            nodes.

         d. The MPLS-TP control plane may provide mechanisms to
            configure the reporting of measurements resulting from
            proactive monitoring.

    125. The MPLS-TP control plane must support the control of the loss
         of continuity (LOC) traffic block consequent action ([RFC6371],
         Section 5.1.2, paragraph 4).

    126. For dynamically established transport paths that have a
         proactive Continuity Check and Connectivity Verification (CC-V)
         function enabled, the control plane must support the signaling
         of the following MEP configuration information ([RFC6371],
         Section 5.1.3):

         a. The MPLS-TP control plane must provide mechanisms to
            configure the MEG identifier to which the MEP belongs.



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         b. The MPLS-TP control plane must provide mechanisms to
            configure a MEP's own identity inside a MEG.

         c. The MPLS-TP control plane must provide mechanisms to
            configure the list of the other MEPs in the MEG.

         d. The MPLS-TP control plane must provide mechanisms to
            configure the CC-V transmission rate / reception period
            (covering all application types).

    127. The MPLS-TP control plane must provide mechanisms to configure
         the generation of Alarm Indication Signal (AIS) packets for
         each MEG ([RFC6371], Section 5.3, paragraph 9).

    128. The MPLS-TP control plane must provide mechanisms to configure
         the generation of Lock Report (LKR) packets for each MEG
         ([RFC6371], Section 5.4, paragraph 9).

    129. The MPLS-TP control plane must provide mechanisms to configure
         the use of proactive Packet Loss Measurement (LM), and the
         transmission rate and Per-Hop Behavior (PHB) class associated
         with the LM OAM packets originating from a MEP ([RFC6371],
         Section 5.5.1, paragraph 1).

    130. The MPLS-TP control plane must provide mechanisms to configure
         the use of proactive Packet Delay Measurement (DM), and the
         transmission rate and PHB class associated with the DM OAM
         packets originating from a MEP ([RFC6371], Section 5.6.1,
         paragraph 1).

    131. The MPLS-TP control plane must provide mechanisms to configure
         the use of Client Failure Indication (CFI), and the
         transmission rate and PHB class associated with the CFI OAM
         packets originating from a MEP ([RFC6371], Section 5.7.1,
         paragraph 1).

    132. The MPLS-TP control plane should provide mechanisms to control
         the use of on-demand CV packets ([RFC6371], Section 6.1).

         a. The MPLS-TP control plane should provide mechanisms to
            configure the number of packets to be transmitted/received
            in each burst of on-demand CV packets and their packet size
            ([RFC6371], Section 6.1.1, paragraph 1).

         b. When an on-demand CV packet is used to check connectivity
            toward a target MIP, the MPLS-TP control plane should
            provide mechanisms to configure the number of hops to reach
            the target MIP ([RFC6371], Section 6.1.1, paragraph 2).



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         c. The MPLS-TP control plane should provide mechanisms to
            configure the PHB of on-demand CV packets ([RFC6371],
            Section 6.1.1, paragraph 3).

    133. The MPLS-TP control plane should provide mechanisms to control
         the use of on-demand LM, including configuration of the
         beginning and duration of the LM procedures, the transmission
         rate, and PHB associated with the LM OAM packets originating
         from a MEP ([RFC6371], Section 6.2.1).

    134. The MPLS-TP control plane should provide mechanisms to control
         the use of throughput estimation ([RFC6371], Section 6.3.1).

    135. The MPLS-TP control plane should provide mechanisms to control
         the use of on-demand DM, including configuration of the
         beginning and duration of the DM procedures, the transmission
         rate, and PHB associated with the DM OAM packets originating
         from a MEP ([RFC6371], Section 6.5.1).

2.4. Security Requirements

   There are no specific MPLS-TP control-plane security requirements.
   The existing framework for MPLS and GMPLS security is documented in
   [RFC5920], and that document applies equally to MPLS-TP.

2.5. Identifier Requirements

   The following are requirements based on [RFC6370]:

    136. The MPLS-TP control plane must support MPLS-TP point-to-point
         tunnel identifiers of the forms defined in Section 5.1 of
         [RFC6370].

    137. The MPLS-TP control plane must support MPLS-TP LSP identifiers
         of the forms defined in Section 5.2 of [RFC6370], and the
         mappings to GMPLS as defined in Section 5.3 of [RFC6370].

    138. The MPLS-TP control plane must support pseudowire path
         identifiers of the form defined in Section 6 of [RFC6370].

    139. The MPLS-TP control plane must support MEG_IDs for LSPs and PWs
         as defined in Section 7.1.1 of [RFC6370].

    140. The MPLS-TP control plane must support IP-compatible MEG_IDs
         for LSPs and PWs as defined in Section 7.1.2 of [RFC6370].

    141. The MPLS-TP control plane must support MEP_IDs for LSPs and PWs
         of the forms defined in Section 7.2.1 of [RFC6370].



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    142. The MPLS-TP control plane must support IP-based MEP_IDs for
         MPLS-TP LSP of the forms defined in Section 7.2.2.1 of
         [RFC6370].

    143. The MPLS-TP control plane must support IP-based MEP_IDs for
         Pseudowires of the form defined in Section 7.2.2.2 of
         [RFC6370].

3. Relationship of PWs and TE LSPs

   The data-plane relationship between PWs and LSPs is inherited from
   standard MPLS and is reviewed in the MPLS-TP framework [RFC5921].
   Likewise, the control-plane relationship between PWs and LSPs is
   inherited from standard MPLS.  This relationship is reviewed in this
   document.  The relationship between the PW and LSP control planes in
   MPLS-TP is the same as the relationship found in the PWE3 Maintenance
   Reference Model as presented in the PWE3 architecture; see Figure 6
   of [RFC3985].  The PWE3 architecture [RFC3985] states: "The PWE3
   protocol-layering model is intended to minimize the differences
   between PWs operating over different PSN types".  Additionally, PW
   control (maintenance) takes place separately from LSP signaling.
   [RFC4447] and [MS-PW-DYNAMIC] provide such extensions for the use of
   LDP as the control plane for PWs.  This control can provide PW
   control without providing LSP control.

   In the context of MPLS-TP, LSP tunnel signaling is provided via GMPLS
   RSVP-TE.  While RSVP-TE could be extended to support PW control much
   as LDP was extended in [RFC4447], such extensions are out of scope of
   this document.  This means that the control of PWs and LSPs will
   operate largely independently.  The main coordination between LSP and
   PW control will occur within the nodes that terminate PWs or PW
   segments.  See Section 5.3.2 for an additional discussion on such
   coordination.

   It is worth noting that the control planes for PWs and LSPs may be
   used independently, and that one may be employed without the other.
   This translates into four possible scenarios: (1) no control plane is
   employed; (2) a control plane is used for both LSPs and PWs; (3) a
   control plane is used for LSPs, but not PWs; (4) a control plane is
   used for PWs, but not LSPs.

   The PW and LSP control planes, collectively, must satisfy the MPLS-TP
   control-plane requirements reviewed in this document.  When client
   services are provided directly via LSPs, all requirements must be
   satisfied by the LSP control plane.  When client services are
   provided via PWs, the PW and LSP control planes can operate in
   combination, and some functions may be satisfied via the PW control
   plane while others are provided to PWs by the LSP control plane.  For



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   example, to support the recovery functions described in [RFC6372],
   this document focuses on the control of the recovery functions at the
   LSP layer.  PW-based recovery is under development at this time and
   may be used once defined.

4. TE LSPs

   MPLS-TP uses Generalized MPLS (GMPLS) signaling and routing, see
   [RFC3945], as the control plane for LSPs.  The GMPLS control plane is
   based on the MPLS control plane.  GMPLS includes support for MPLS
   labeled data and transport data planes.  GMPLS includes most of the
   transport-centric features required to support MPLS-TP LSPs.  This
   section will first review the features of GMPLS relevant to MPLS-TP
   LSPs, then identify how specific requirements can be met using
   existing GMPLS functions, and will conclude with extensions that are
   anticipated to support the remaining MPLS-TP control-plane
   requirements.

4.1.  GMPLS Functions and MPLS-TP LSPs

   This section reviews how existing GMPLS functions can be applied to
   MPLS-TP.

4.1.1.  In-Band and Out-of-Band Control

   GMPLS supports both in-band and out-of-band control.  The terms "in-
   band" and "out-of-band", in the context of this document, refer to
   the relationship of the control plane relative to the management and
   data planes.  The terms may be used to refer to the control plane
   independent of the management plane, or to both of them in concert.
   The remainder of this section describes the relationship of the
   control plane to the management and data planes.

   There are multiple uses of both terms "in-band" and "out-of-band".
   The terms may relate to a channel, a path, or a network.  Each of
   these can be used independently or in combination.  Briefly, some
   typical usage of the terms is as follows:

   o  In-band
      This term is used to refer to cases where control-plane traffic is
      sent in the same communication channel used to transport
      associated user data or management traffic.  IP, MPLS, and
      Ethernet networks are all examples where control traffic is
      typically sent in-band with the data traffic.  An example of this
      case in the context of MPLS-TP is where control-plane traffic is
      sent via the MPLS Generic Associated Channel (G-ACh), see
      [RFC5586], using the same LSP as controlled user traffic.




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   o  Out-of-band, in-fiber (same physical connection)
      This term is used to refer to cases where control-plane traffic is
      sent using a different communication channel from the associated
      data or management traffic, and the control communication channel
      resides in the same fiber as either the management or data
      traffic.  An example of this case in the context of MPLS-TP is
      where control-plane traffic is sent via the G-ACh using a
      dedicated LSP on the same link (interface) that carries controlled
      user traffic.

   o  Out-of-band, aligned topology
      This term is used to refer to the cases where control-plane
      traffic is sent using a different communication channel from the
      associated data or management traffic, and the control traffic
      follows the same node-to-node path as either the data or
      management traffic.

      Such topologies are usually supported using a parallel fiber or
      other configurations where multiple data channels are available
      and one is (dynamically) selected as the control channel.  An
      example of this case in the context of MPLS-TP is where control-
      plane traffic is sent along the same nodal path, but not
      necessarily the same links (interfaces), as the corresponding
      controlled user traffic.

   o  Out-of-band, independent topology
      This term is used to refer to the cases where control-plane
      traffic is sent using a different communication channel from the
      associated data or management traffic, and the control traffic may
      follow a path that is completely independent of the data traffic.

      Such configurations are a superset of the other cases and do not
      preclude the use of in-fiber or aligned topology links, but
      alignment is not required.  An example of this case in the context
      of MPLS-TP is where control-plane traffic is sent between
      controlling nodes using any available path and links, completely
      without regard for the path(s) taken by corresponding management
      or user traffic.

   In the context of MPLS-TP requirements, requirement 14 (see Section 2
   above) can be met using out-of-band in-fiber or aligned topology
   types of control.  Requirement 15 can only be met by using out-of-
   band, independent topology.  G-ACh is likely to be used extensively
   in MPLS-TP networks to support the MPLS-TP control (and management)
   planes.






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4.1.2. Addressing

   MPLS-TP reuses and supports the addressing mechanisms supported by
   MPLS.  The MPLS-TP identifiers document (see [RFC6370]) provides
   additional context on how IP addresses are used within MPLS-TP.
   MPLS, and consequently MPLS-TP, uses the IPv4 and IPv6 address
   families to identify MPLS-TP nodes by default for network management
   and signaling purposes.  The address spaces and neighbor adjacencies
   in the control, management, and data planes used in an MPLS-TP
   network may be completely separated or combined at the discretion of
   an MPLS-TP operator and based on the equipment capabilities of a
   vendor.  The separation of the control and management planes from the
   data plane allows each plane to be independently addressable.  Each
   plane may use addresses that are not mutually reachable, e.g., it is
   likely that the data plane will not be able to reach an address from
   the management or control planes and vice versa.  Each plane may also
   use a different address family.  It is even possible to reuse
   addresses in each plane, but this is not recommended as it may lead
   to operational confusion.  As previously mentioned, the G-ACh
   mechanism defined in [RFC5586] is expected to be used extensively in
   MPLS-TP networks to support the MPLS-TP control (and management)
   planes.

4.1.3.  Routing

   Routing support for MPLS-TP LSPs is based on GMPLS routing.  GMPLS
   routing builds on TE routing and has been extended to support
   multiple switching technologies per [RFC3945] and [RFC4202] as well
   as multiple levels of packet switching within a single network.  IS-
   IS extensions for GMPLS are defined in [RFC5307] and [RFC5316], which
   build on the TE extensions to IS-IS defined in [RFC5305].  OSPF
   extensions for GMPLS are defined in [RFC4203] and [RFC5392], which
   build on the TE extensions to OSPF defined in [RFC3630].  The listed
   RFCs should be viewed as a starting point rather than a comprehensive
   list as there are other IS-IS and OSPF extensions, as defined in IETF
   RFCs, that can be used within an MPLS-TP network.

4.1.4.  TE LSPs and Constraint-Based Path Computation

   Both MPLS and GMPLS allow for traffic engineering and constraint-
   based path computation.  MPLS path computation provides paths for
   MPLS-TE unidirectional P2P and P2MP LSPs.  GMPLS path computation
   adds bidirectional LSPs, explicit recovery path computation, as well
   as support for the other functions discussed in this section.

   Both MPLS and GMPLS path computation allow for the restriction of
   path selection based on the use of Explicit Route Objects (EROs) and
   other LSP attributes; see [RFC3209] and [RFC3473].  In all cases, no



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   specific algorithm is standardized by the IETF.  This is anticipated
   to continue to be the case for MPLS-TP LSPs.

4.1.4.1.  Relation to PCE

   Path Computation Element (PCE)-based approaches, see [RFC4655], may
   be used for path computation of a GMPLS LSP, and consequently an
   MPLS-TP LSP, across domains and in a single domain.  In cases where
   PCE is used, the PCE Communication Protocol (PCEP), see [RFC5440],
   will be used to communicate PCE-related requests and responses.
   MPLS-TP-specific extensions to PCEP are currently out of scope of the
   MPLS-TP project and this document.

4.1.5.  Signaling

   GMPLS signaling is defined in [RFC3471] and [RFC3473] and is based on
   RSVP-TE [RFC3209].  Constraint-based Routed LDP (CR-LDP) GMPLS (see
   [RFC3472]) is no longer under active development within the IETF,
   i.e., it is deprecated (see [RFC3468]) and must not be used for MPLS
   nor MPLS-TP consequently.  In general, all RSVP-TE extensions that
   apply to MPLS may also be used for GMPLS and consequently MPLS-TP.
   Most notably, this includes support for P2MP signaling as defined in
   [RFC4875].

   GMPLS signaling includes a number of MPLS-TP required functions --
   notably, support for out-of-band control, bidirectional LSPs, and
   independent control- and data-plane fault management.  There are also
   numerous other GMPLS and MPLS extensions that can be used to provide
   specific functions in MPLS-TP networks.  Specific references are
   provided below.

4.1.6.  Unnumbered Links

   Support for unnumbered links (i.e., links that do not have IP
   addresses) is permitted in MPLS-TP and its usage is at the discretion
   of the network operator.  Support for unnumbered links is included
   for routing using OSPF [RFC4203] and IS-IS [RFC5307], and for
   signaling in [RFC3477].

4.1.7.  Link Bundling

   Link bundling provides a local construct that can be used to improve
   scaling of TE routing when multiple data links are shared between
   node pairs.  Link bundling for MPLS and GMPLS networks is defined in
   [RFC4201].  Link bundling may be used in MPLS-TP networks, and its
   use is at the discretion of the network operator.





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4.1.8.  Hierarchical LSPs

   This section reuses text from [RFC6107].

   [RFC3031] describes how MPLS labels may be stacked so that LSPs may
   be nested with one LSP running through another.  This concept of
   hierarchical LSPs (H-LSPs) is formalized in [RFC4206] with a set of
   protocol mechanisms for the establishment of a hierarchical LSP that
   can carry one or more other LSPs.

   [RFC4206] goes on to explain that a hierarchical LSP may carry other
   LSPs only according to their switching types.  This is a function of
   the way labels are carried.  In a packet switch capable network, the
   hierarchical LSP can carry other packet switch capable LSPs using the
   MPLS label stack.

   Signaling mechanisms defined in [RFC4206] allow a hierarchical LSP to
   be treated as a single hop in the path of another LSP.  This
   mechanism is also sometimes known as "non-adjacent signaling", see
   [RFC4208].

   A Forwarding Adjacency (FA) is defined in [RFC4206] as a data link
   created from an LSP and advertised in the same instance of the
   control plane that advertises the TE links from which the LSP is
   constructed.  The LSP itself is called an FA-LSP.  FA-LSPs are
   analogous to MPLS-TP Sections as discussed in [RFC5960].

   Thus, a hierarchical LSP may form an FA such that it is advertised as
   a TE link in the same instance of the routing protocol as was used to
   advertise the TE links that the LSP traverses.

   As observed in [RFC4206], the nodes at the ends of an FA would not
   usually have a routing adjacency.

   LSP hierarchy is expected to play an important role in MPLS-TP
   networks, particularly in the context of scaling and recovery as well
   as supporting SPMEs.

4.1.9.  LSP Recovery

   GMPLS defines RSVP-TE extensions in support for end-to-end GMPLS LSPs
   recovery in [RFC4872] and segment recovery in [RFC4873].  GMPLS
   segment recovery provides a superset of the function in end-to-end
   recovery.  End-to-end recovery can be viewed as a special case of
   segment recovery where there is a single recovery domain whose
   borders coincide with the ingress and egress of the LSP, although
   specific procedures are defined.




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   The five defined types of recovery defined in GMPLS are:

      - 1+1 bidirectional protection for P2P LSPs
      - 1+1 unidirectional protection for P2MP LSPs
      - 1:n (including 1:1) protection with or without extra traffic
      - Rerouting without extra traffic (sometimes known as soft
        rerouting), including shared mesh restoration
      - Full LSP rerouting

   Recovery for MPLS-TP LSPs, as discussed in [RFC6372], is signaled
   using the mechanism defined in [RFC4872] and [RFC4873].  Note that
   when MEPs are required for the OAM CC function and the MEPs exist at
   LSP transit nodes, each MEP is instantiated at a hierarchical LSP end
   point, and protection is provided end-to-end for the hierarchical
   LSP.  (Protection can be signaled using either [RFC4872] or [RFC4873]
   defined procedures.)  The use of Notify messages to trigger
   protection switching and recovery is not required in MPLS-TP, as this
   function is expected to be supported via OAM.  However, its use is
   not precluded.

4.1.10.  Control-Plane Reference Points (E-NNI, I-NNI, UNI)

   The majority of RFCs about the GMPLS control plane define the control
   plane from the context of an internal Network-to-Network Interface
   (I-NNI).  In the MPLS-TP context, some operators may choose to deploy
   signaled interfaces across User-to-Network Interfaces (UNIs) and
   across inter-provider, external Network-to-Network Interfaces
   (E-NNIs).  Such support is embodied in [RFC4208] for UNIs and in
   [RFC5787] for routing areas in support of E-NNIs.  This work may
   require extensions in order to meet the specific needs of an MPLS-TP
   UNI and E-NNI.

4.2.  OAM, MEP (Hierarchy), MIP Configuration and Control

   MPLS-TP is defined to support a comprehensive set of MPLS-TP OAM
   functions.  The MPLS-TP control plane will not itself provide OAM
   functions, but it will be used to instantiate and otherwise control
   MPLS-TP OAM functions.

   Specific OAM requirements for MPLS-TP are documented in [RFC5860].
   This document also states that it is required that the control plane
   be able to configure and control OAM entities.  This requirement is
   not yet addressed by the existing RFCs, but such work is now under
   way, e.g., [CCAMP-OAM-FWK] and [CCAMP-OAM-EXT].

   Many OAM functions occur on a per-LSP basis, are typically in-band,
   and are initiated immediately after LSP establishment.  Hence, it is
   desirable that such functions be established and activated via the



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   same control-plane signaling used to set up the LSP, as this
   effectively synchronizes OAM with the LSP lifetime and avoids the
   extra overhead and potential errors associated with separate OAM
   configuration mechanisms.

4.2.1.  Management-Plane Support

   There is no MPLS-TP requirement for a standardized management
   interface to the MPLS-TP control plane.  That said, MPLS and GMPLS
   support a number of standardized management functions.  These include
   the MPLS-TE/GMPLS TE Database Management Information Base [TE-MIB];
   the MPLS-TE MIB [RFC3812]; the MPLS LSR MIB [RFC3813]; the GMPLS TE
   MIB [RFC4802]; and the GMPLS LSR MIB [RFC4803].  These MIB modules
   may be used in MPLS-TP networks.  A general overview of MPLS-TP
   related MIB modules can be found in [TP-MIB].  Network management
   requirements for MPLS-based transport networks are provided in
   [RFC5951].

4.2.1.1.  Recovery Triggers

   The GMPLS control plane allows for management-plane recovery triggers
   and directly supports control-plane recovery triggers.  Support for
   control-plane recovery triggers is defined in [RFC4872], which refers
   to the triggers as "Recovery Commands".  These commands can be used
   with both end-to-end and segment recovery, but are always controlled
   on an end-to-end basis.  The recovery triggers/commands defined in
   [RFC4872] are:

      a. Lockout of recovery LSP

      b. Lockout of normal traffic

      c. Forced switch for normal traffic

      d. Requested switch for normal traffic

      e. Requested switch for recovery LSP

   Note that control-plane triggers are typically invoked in response to
   a management-plane request at the ingress.

4.2.1.2.  Management-Plane / Control-Plane Ownership Transfer

   In networks where both the control plane and management plane are
   provided, LSP provisioning can be done either by the control plane or
   management plane.  As mentioned in the requirements section above, it
   must be possible to transfer, or handover, a management-plane-created
   LSP to the control-plane domain and vice versa.  [RFC5493] defines



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   the specific requirements for an LSP ownership handover procedure.
   It must be possible for the control plane to provide the management
   plane, in a reliable manner, with the status or result of an
   operation performed by the management plane.  This notification may
   be either synchronous or asynchronous with respect to the operation.
   Moreover, it must be possible for the management plane to monitor the
   status of the control plane, for example, the status of a TE link,
   its available resources, etc.  This monitoring may be based on
   queries initiated by the management plane or on notifications
   generated by the control plane.  A mechanism must be made available
   by the control plane to the management plane to log operation of a
   control-plane LSP; that is, it must be possible from the NMS to have
   a clear view of the life (traffic hit, action performed, signaling,
   etc.) of a given LSP.  The LSP handover procedure for MPLS-TP LSPs is
   supported via [RFC5852].

4.3.  GMPLS and MPLS-TP Requirements Table

   The following table shows how the MPLS-TP control-plane requirements
   can be met using the existing GMPLS control plane (which builds on
   the MPLS control plane).  Areas where additional specifications are
   required are also identified.  The table lists references based on
   the control-plane requirements as identified and numbered above in
   Section 2.

   +=======+===========================================================+
   | Req # | References                                                |
   +-------+-----------------------------------------------------------+
   |    1  | Generic requirement met by using Standards Track RFCs     |
   |    2  | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307]     |
   |    3  | [RFC5145] + Formal Definition (See Section 4.4.1)         |
   |    4  | Generic requirement met by using Standards Track RFCs     |
   |    5  | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307]     |
   |    6  | [RFC3471], [RFC3473], [RFC4875]                           |
   |    7  | [RFC3471], [RFC3473] +                                    |
   |       |    Associated bidirectional LSPs (See Section 4.4.2)      |
   |    8  | [RFC4875]                                                 |
   |    9  | [RFC3473]                                                 |
   |   10  | Associated bidirectional LSPs (See Section 4.4.2)         |
   |   11  | Associated bidirectional LSPs (See Section 4.4.2)         |
   |   12  | [RFC3473]                                                 |
   |   13  | [RFC5467] (Currently Experimental; See Section 4.4.3)     |
   |   14  | [RFC3945], [RFC3473], [RFC4202], [RFC4203], [RFC5307]     |
   |   15  | [RFC3945], [RFC3473], [RFC4202], [RFC4203], [RFC5307]     |
   |   16  | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307]     |
   |   17  | [RFC3945], [RFC4202] + proper vendor implementation       |
   |   18  | [RFC3945], [RFC4202] + proper vendor implementation       |
   |   19  | [RFC3945], [RFC4202]                                      |



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   |   20  | [RFC3473]                                                 |
   |   21  | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307],    |
   |       |     [RFC5151]                                             |
   |   22  | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307],    |
   |       |     [RFC5151]                                             |
   |   23  | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307]     |
   |   24  | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307]     |
   |   25  | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307],    |
   |       |     [RFC6107]                                             |
   |   26  | [RFC3473], [RFC4875]                                      |
   |   27  | [RFC3473], [RFC4875]                                      |
   |   28  | [RFC3945], [RFC3471], [RFC4202]                           |
   |   29  | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307]     |
   |   30  | [RFC3945], [RFC3471], [RFC4202]                           |
   |   31  | [RFC3945], [RFC3471], [RFC4202]                           |
   |   32  | [RFC4208], [RFC4974], [RFC5787], [RFC6001]                |
   |   33  | [RFC3473], [RFC4875]                                      |
   |   34  | [RFC4875]                                                 |
   |   35  | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307]     |
   |   36  | [RFC3473], [RFC3209] (Make-before-break)                  |
   |   37  | [RFC3473], [RFC3209] (Make-before-break)                  |
   |   38  | [RFC4139], [RFC4258], [RFC5787]                           |
   |   39  | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307]     |
   |   40  | [RFC3473], [RFC5063]                                      |
   |   41  | [RFC3945], [RFC3471], [RFC4202], [RFC4208]                |
   |   42  | [RFC3945], [RFC3471], [RFC4202]                           |
   |   43  | [RFC4872], [RFC4873], [CCAMP-OAM-FWK], [CCAMP-OAM-EXT]    |
   |   44  | [RFC6107], [CCAMP-OAM-FWK], [CCAMP-OAM-EXT]               |
   |   45  | [RFC3473], [RFC4203], [RFC5307], [RFC5063]                |
   |   46  | [RFC5493]                                                 |
   |   47  | [RFC4872], [RFC4873]                                      |
   |   48  | [RFC3945], [RFC3471], [RFC4202]                           |
   |   49  | [RFC4872], [RFC4873] + Recovery for P2MP (see Sec. 4.4.4) |
   |   50  | [RFC4872], [RFC4873]                                      |
   |   51  | [RFC4872], [RFC4873] + proper vendor implementation       |
   |   52  | [RFC4872], [RFC4873], [GMPLS-PS]                          |
   |   53  | [RFC4872], [RFC4873]                                      |
   |   54  | [RFC3473], [RFC4872], [RFC4873], [GMPLS-PS]               |
   |       |     Timers are a local implementation matter              |
   |   55  | [RFC4872], [RFC4873], [GMPLS-PS] +                        |
   |       |     implementation of timers                              |
   |   56  | [RFC4872], [RFC4873], [GMPLS-PS]                          |
   |   57  | [RFC4872], [RFC4873]                                      |
   |   58  | [RFC4872], [RFC4873]                                      |
   |   59  | [RFC4872], [RFC4873]                                      |
   |   60  | [RFC4872], [RFC4873], [RFC6107]                           |
   |   61  | [RFC4872], [RFC4873]                                      |
   |   62  | [RFC4872], [RFC4873] + Recovery for P2MP (see Sec. 4.4.4) |



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   |   63  | [RFC4872], [RFC4873]                                      |
   |   64  | [RFC4872], [RFC4873]                                      |
   |   65  | [RFC4872], [RFC4873]                                      |
   |   66  | [RFC4872], [RFC4873], [RFC6107]                           |
   |   67  | [RFC4872], [RFC4873]                                      |
   |   68  | [RFC3473], [RFC4872], [RFC4873]                           |
   |   69  | [RFC3473]                                                 |
   |   70  | [RFC3473], [RFC4872], [GMPLS-PS]                          |
   |   71  | [RFC3473], [RFC4872]                                      |
   |   72  | [RFC4872], [RFC4873], [CCAMP-OAM-FWK], [CCAMP-OAM-EXT]    |
   |   73  | [RFC4426], [RFC4872], [RFC4873]                           |
   |   74  | [RFC4426], [RFC4872], [RFC4873]                           |
   |   75  | [RFC4426], [RFC4872], [RFC4873]                           |
   |   76  | [RFC4426], [RFC4872], [RFC4873]                           |
   |   77  | [RFC4426], [RFC4872], [RFC4873]                           |
   |   78  | [RFC4426], [RFC4872], [RFC4873] + vendor implementation   |
   |   79  | [RFC4426], [RFC4872], [RFC4873]                           |
   |   80  | [RFC4426], [RFC4872], [RFC4873]                           |
   |   81  | [RFC4872], [RFC4873] + Testing control (See Sec. 4.4.5)   |
   |   82  | [RFC4872], [RFC4873] + Testing control (See Sec. 4.4.5)   |
   |   83  | [RFC4872], [RFC4873] + Testing control (See Sec. 4.4.5)   |
   |   84  | [RFC4872], [RFC4873] + Testing control (See Sec. 4.4.5)   |
   |   85  | [RFC4872], [RFC4873], [CCAMP-OAM-FWK], [CCAMP-OAM-EXT]    |
   |   86  | [RFC4872], [RFC4873]                                      |
   |   87  | [RFC4872], [RFC4873]                                      |
   |   88  | [RFC4872], [RFC4873], [TP-RING]                           |
   |   89  | [RFC4872], [RFC4873], [TP-RING]                           |
   |   90  | [RFC3270], [RFC3473], [RFC4124] + GMPLS Usage (See 4.4.6) |
   |   91  | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307]     |
   |   92  | [RFC3945], [RFC3473], [RFC2210], [RFC2211], [RFC2212]     |
   |   93  | Generic requirement on data plane (correct implementation)|
   |   94  | [RFC3473], [NO-PHP]                                       |
   |   95  | [RFC3270], [RFC3473], [RFC4124] + GMPLS Usage (See 4.4.6) |
   |   96  | PW only requirement; see PW Requirements Table (5.2)      |
   |   97  | PW only requirement; see PW Requirements Table (5.2)      |
   |   98  | [RFC3945], [RFC3473], [RFC6107]                           |
   |   99  | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307] +   |
   |       |      [RFC5392] and [RFC5316]                              |
   |  100  | PW only requirement; see PW Requirements Table (5.2)      |
   |  101  | [RFC3473], [RFC4203], [RFC5307], [RFC5063]                |
   |  102  | [RFC4872], [RFC4873], [TP-RING]                           |
   |  103  | [RFC3945], [RFC3473], [RFC6107]                           |
   |  104  | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT]                          |
   |  105  | [RFC3473], [CCAMP-OAM-FWK], [CCAMP-OAM-EXT]               |
   |  106  | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT]                          |
   |  107  | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] + (See Sec. 4.4.5)       |
   |  108  | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT]                          |
   |  109  | [RFC3473], [RFC4872], [RFC4873]                           |



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   |  110  | [RFC3473], [RFC4872], [RFC4873]                           |
   |  111  | [RFC3473], [RFC4783]                                      |
   |  112  | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT]                          |
   |  113  | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] + (See Sec. 4.4.5)       |
   |  114  | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] + (See Sec. 4.4.5)       |
   |  115  | [RFC3473]                                                 |
   |  116  | [RFC4426], [RFC4872], [RFC4873]                           |
   |  117  | [RFC3473], [RFC4872], [RFC4873]                           |
   |  118  | [RFC3473], [RFC4783]                                      |
   |  119  | [RFC3473]                                                 |
   |  120  | [RFC3473], [RFC4783]                                      |
   |  121  | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] + (See Sec. 4.4.5)       |
   |  122  | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] + (See Sec. 4.4.5)       |
   |  123  | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT], [RFC6107]               |
   | 124 - |                                                           |
   |   135 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] + (See Sec. 4.4.5)       |
   |  136a | [RFC3473]                                                 |
   |  136b | [RFC3473] + (See Sec. 4.4.7)                              |
   |  137a | [RFC3473]                                                 |
   |  137b | [RFC3473] + (See Sec. 4.4.7)                              |
   |  138  | PW only requirement; see PW Requirements Table (5.2)      |
   | 139 - |                                                           |
   |   143 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] + (See Sec. 4.4.8)       |
   +=======+===========================================================+

               Table 1: GMPLS and MPLS-TP Requirements Table

4.4.  Anticipated MPLS-TP-Related Extensions and Definitions

   This section identifies the extensions and other documents that have
   been identified as likely to be needed to support the full set of
   MPLS-TP control-plane requirements.

4.4.1.  MPLS-TE to MPLS-TP LSP Control-Plane Interworking

   While no interworking function is expected in the data plane to
   support the interconnection of MPLS-TE and MPLS-TP networking, this
   is not the case for the control plane.  MPLS-TE networks typically
   use LSP signaling based on [RFC3209], while MPLS-TP LSPs will be
   signaled using GMPLS RSVP-TE, i.e., [RFC3473].  [RFC5145] identifies
   a set of solutions that are aimed to aid in the interworking of MPLS-
   TE and GMPLS control planes.  [RFC5145] work will serve as the
   foundation for a formal definition of MPLS to MPLS-TP control-plane
   interworking.







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4.4.2.  Associated Bidirectional LSPs

   GMPLS signaling, [RFC3473], supports unidirectional and co-routed,
   bidirectional point-to-point LSPs.  MPLS-TP also requires support for
   associated bidirectional point-to-point LSPs.  Such support will
   require an extension or a formal definition of how the LSP end points
   supporting an associated bidirectional service will coordinate the
   two LSPs used to provide such a service.  Per requirement 11, transit
   nodes that support an associated bidirectional service should be
   aware of the association of the LSPs used to support the service when
   both LSPs are supported on that transit node.  There are several
   existing protocol mechanisms on which to base such support,
   including, but not limited to:

      o  GMPLS calls [RFC4974].

      o  The ASSOCIATION object [RFC4872].

      o  The LSP_TUNNEL_INTERFACE_ID object [RFC6107].

4.4.3.  Asymmetric Bandwidth LSPs

   [RFC5467] defines support for bidirectional LSPs that have different
   (asymmetric) bandwidth requirements for each direction.  That RFC can
   be used to meet the related MPLS-TP technical requirement, but it is
   currently an Experimental RFC.  To fully satisfy the MPLS-TP
   requirement, RFC 5467 will need to become a Standards Track RFC.

4.4.4.  Recovery for P2MP LSPs

   The definitions of P2MP, [RFC4875], and GMPLS recovery, [RFC4872] and
   [RFC4873], do not explicitly cover their interactions.  MPLS-TP
   requires a formal definition of recovery techniques for P2MP LSPs.
   Such a formal definition will be based on existing RFCs and may not
   require any new protocol mechanisms but, nonetheless, must be
   documented.

4.4.5.  Test Traffic Control and Other OAM Functions

   [CCAMP-OAM-FWK] and [CCAMP-OAM-EXT] are examples of OAM-related
   control extensions to GMPLS.  These extensions cover a portion of,
   but not all, OAM-related control functions that have been identified
   in the context of MPLS-TP.  As discussed above, the MPLS-TP control
   plane must support the selection of which OAM function(s) (if any) to
   use (including support to select experimental OAM functions) and what
   OAM functionality to run, including Continuity Check (CC),





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   Connectivity Verification (CV), packet loss, delay quantification,
   and diagnostic testing of a service.  Such support may be included in
   the listed documents or in other documents.

4.4.6.  Diffserv Object Usage in GMPLS

   [RFC3270] and [RFC4124] define support for Diffserv-enabled MPLS
   LSPs.  While [RFC4124] references GMPLS signaling, there is no
   explicit discussion on the use of the Diffserv-related objects in
   GMPLS signaling.  A (possibly Informational) document on how GMPLS
   supports Diffserv LSPs is likely to prove useful in the context of
   MPLS-TP.

4.4.7.  Support for MPLS-TP LSP Identifiers

   MPLS-TP uses two forms of LSP identifiers, see [RFC6370].  One form
   is based on existing GMPLS fields.  The other form is based on either
   the globally unique Attachment Interface Identifier (AII) defined in
   [RFC5003] or the ITU Carrier Code (ICC) defined in ITU-T
   Recommendation M.1400.  Neither form is currently supported in GMPLS,
   and such extensions will need to be documented.

4.4.8.  Support for MPLS-TP Maintenance Identifiers

   MPLS-TP defines several forms of maintenance-entity-related
   identifiers.  Both node-unique and global forms are defined.
   Extensions will be required to GMPLS to support these identifiers.
   These extensions may be added to existing works in progress, such as
   [CCAMP-OAM-FWK] and [CCAMP-OAM-EXT], or may be defined in independent
   documents.

5.  Pseudowires

5.1.  LDP Functions and Pseudowires

   MPLS PWs are defined in [RFC3985] and [RFC5659], and provide for
   emulated services over an MPLS Packet Switched Network (PSN).
   Several types of PWs have been defined: (1) Ethernet PWs providing
   for Ethernet port or Ethernet VLAN transport over MPLS [RFC4448], (2)
   High-Level Data Link Control (HDLC) / PPP PW providing for HDLC/PPP
   leased line transport over MPLS [RFC4618], (3) ATM PWs [RFC4816], (4)
   Frame Relay PWs [RFC4619], and (5) circuit Emulation PWs [RFC4553].

   Today's transport networks based on Plesiochronous Digital Hierarchy
   (PDH), WDM, or SONET/SDH provide transport for PDH or SONET (e.g.,
   ATM over SONET or Packet PPP over SONET) client signals with no
   payload awareness.  Implementing PW capability allows for the use of
   an existing technology to substitute the Time-Division Multiplexing



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   (TDM) transport with packet-based transport, using well-defined PW
   encapsulation methods for carrying various packet services over MPLS,
   and providing for potentially better bandwidth utilization.

   There are two general classes of PWs: (1) Single-Segment Pseudowires
   (SS-PWs) [RFC3985] and (2) Multi-segment Pseudowires (MS-PWs)
   [RFC5659].  An MPLS-TP network domain may transparently transport a
   PW whose end points are within a client network.  Alternatively, an
   MPLS-TP edge node may be the Terminating PE (T-PE) for a PW,
   performing adaptation from the native attachment circuit technology
   (e.g., Ethernet 802.1Q) to an MPLS PW that is then transported in an
   LSP over an MPLS-TP network.  In this way, the PW is analogous to a
   transport channel in a TDM network, and the LSP is equivalent to a
   container of multiple non-concatenated channels, albeit they are
   packet containers.  An MPLS-TP network may also contain Switching PEs
   (S-PEs) for a Multi-Segment PW whereby the T-PEs may be at the edge
   of an MPLS-TP network or in a client network.  In the latter case, a
   T-PE in a client network performs the adaptation of the native
   service to MPLS and the MPLS-TP network performs pseudowire
   switching.

   The SS-PW signaling control plane is based on targeted LDP (T-LDP)
   with specific procedures defined in [RFC4447].  The MS-PW signaling
   control plane is also based on T-LDP as allowed for in [RFC5659],
   [RFC6073], and [MS-PW-DYNAMIC].  An MPLS-TP network shall use the
   same PW signaling protocols and procedures for placing SS-PWs and
   MS-PWs.  This will leverage existing technology as well as facilitate
   interoperability with client networks with native attachment circuits
   or PW segments that are switched across an MPLS-TP network.

5.1.1.  Management-Plane Support

   There is no MPLS-TP requirement for a standardized management
   interface to the MPLS-TP control plane.  A general overview of MPLS-
   TP-related MIB modules can be found in [TP-MIB].  Network management
   requirements for MPLS-based transport networks are provided in
   [RFC5951].

5.2.  PW Control (LDP) and MPLS-TP Requirements Table

   The following table shows how the MPLS-TP control-plane requirements
   can be met using the existing LDP control plane for pseudowires
   (targeted LDP).  Areas where additional specifications are required
   are also identified.  The table lists references based on the
   control-plane requirements as identified and numbered above in
   Section 2.





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   In the table below, several of the requirements shown are addressed
   -- in part or in full -- by the use of MPLS-TP LSPs to carry
   pseudowires.  This is reflected by including "TP-LSPs" as a reference
   for those requirements.  Section 5.3.2 provides additional context
   for the binding of PWs to TP-LSPs.














































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   +=======+===========================================================+
   | Req # | References                                                |
   +-------+-----------------------------------------------------------+
   |    1  | Generic requirement met by using Standards Track RFCs     |
   |    2  | [RFC3985], [RFC4447], Together with TP-LSPs (Sec. 4.3)    |
   |    3  | [RFC3985], [RFC4447]                                      |
   |    4  | Generic requirement met by using Standards Track RFCs     |
   |    5  | [RFC3985], [RFC4447], Together with TP-LSPs               |
   |    6  | [RFC3985], [RFC4447], [PW-P2MPR], [PW-P2MPE] + TP-LSPs    |
   |    7  | [RFC3985], [RFC4447], + TP-LSPs                           |
   |    8  | [PW-P2MPR], [PW-P2MPE]                                    |
   |    9  | [RFC3985], end-node only involvement for PW               |
   |   10  | [RFC3985], proper vendor implementation                   |
   |   11  | [RFC3985], end-node only involvement for PW               |
   | 12-13 | [RFC3985], [RFC4447], See Section 5.3.4                   |
   |   14  | [RFC3985], [RFC4447]                                      |
   |   15  | [RFC4447], [RFC3478], proper vendor implementation        |
   |   16  | [RFC3985], [RFC4447]                                      |
   | 17-18 | [RFC3985], proper vendor implementation                   |
   | 19-26 | [RFC3985], [RFC4447], [RFC5659], implementation           |
   |   27  | [RFC4448], [RFC4816], [RFC4618], [RFC4619], [RFC4553]     |
   |       | [RFC4842], [RFC5287]                                      |
   |   28  | [RFC3985]                                                 |
   | 29-31 | [RFC3985], [RFC4447]                                      |
   |   32  | [RFC3985], [RFC4447], [RFC5659], See Section 5.3.6        |
   |   33  | [RFC4385], [RFC4447], [RFC5586]                           |
   |   34  | [PW-P2MPR], [PW-P2MPE]                                    |
   |   35  | [RFC4863]                                                 |
   | 36-37 | [RFC3985], [RFC4447], See Section 5.3.4                   |
   |   38  | Provided by TP-LSPs                                       |
   |   39  | [RFC3985], [RFC4447], + TP-LSPs                           |
   |   40  | [RFC3478]                                                 |
   | 41-42 | [RFC3985], [RFC4447]                                      |
   | 43-44 | [RFC3985], [RFC4447], + TP-LSPs - See Section 5.3.5       |
   |   45  | [RFC3985], [RFC4447], [RFC5659] + TP-LSPs                 |
   |   46  | [RFC3985], [RFC4447], + TP-LSPs - See Section 5.3.3       |
   |   47  | [PW-RED], [PW-REDB]                                       |
   | 48-49 | [RFC3985], [RFC4447], + TP-LSPs, implementation           |
   | 50-52 | Provided by TP-LSPs, and Section 5.3.5                    |
   | 53-55 | [RFC3985], [RFC4447], See Section 5.3.5                   |
   |   56  | [PW-RED], [PW-REDB]                                       |
   |       | revertive/non-revertive behavior is a local matter for PW |
   | 57-58 | [PW-RED], [PW-REDB]                                       |
   | 59-81 | [RFC3985], [RFC4447], [PW-RED], [PW-REDB], Section 5.3.5  |
   | 82-83 | [RFC5085], [RFC5586], [RFC5885]                           |
   | 84-89 | [RFC3985], [RFC4447], [PW-RED], [PW-REDB], Section 5.3.5  |
   | 90-95 | [RFC3985], [RFC4447], + TP-LSPs, implementation           |
   |   96  | [RFC4447], [MS-PW-DYNAMIC]                                |



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   |   97  | [RFC4447]                                                 |
   |  98 - |                                                           |
   |   99  | Not Applicable to PW                                      |
   |  100  | [RFC4447]                                                 |
   |  101  | [RFC3478]                                                 |
   |  102  | [RFC3985], + TP-LSPs                                      |
   |  103  | Not Applicable to PW                                      |
   |  104  | [PW-OAM]                                                  |
   |  105  | [PW-OAM]                                                  |
   | 106 - |                                                           |
   |   108 | [RFC5085], [RFC5586], [RFC5885]                           |
   |  109  | [RFC5085], [RFC5586], [RFC5885]                           |
   |       | fault reporting and protection triggering is a local      |
   |       | matter for PW                                             |
   |  110  | [RFC5085], [RFC5586], [RFC5885]                           |
   |       | fault reporting and protection triggering is a local      |
   |       | matter for PW                                             |
   |  111  | [RFC4447]                                                 |
   |  112  | [RFC4447], [RFC5085], [RFC5586], [RFC5885]                |
   |  113  | [RFC5085], [RFC5586], [RFC5885]                           |
   |  114  | [RFC5085], [RFC5586], [RFC5885]                           |
   |  115  | path traversed by PW is determined by LSP path; see       |
   |       | GMPLS and MPLS-TP Requirements Table, Section 4.3         |
   |  116  | [PW-RED], [PW-REDB], administrative control of redundant  |
   |       | PW is a local matter at the PW head-end                   |
   |  117  | [PW-RED], [PW-REDB], [RFC5085], [RFC5586], [RFC5885]      |
   |  118  | [RFC3985], [RFC4447], [PW-RED], [PW-REDB], Section 5.3.5  |
   |  119  | [RFC4447]                                                 |
   | 120 - |                                                           |
   |   125 | [RFC5085], [RFC5586], [RFC5885]                           |
   | 126 - |                                                           |
   |   130 | [PW-OAM]                                                  |
   |  131  | Section 5.3.5                                             |
   |  132  | [PW-OAM]                                                  |
   |  133  | [PW-OAM]                                                  |
   |  134  | Section 5.3.5                                             |
   |  135  | [PW-OAM]                                                  |
   |  136  | Not Applicable to PW                                      |
   |  137  | Not Applicable to PW                                      |
   |  138  | [RFC4447], [RFC5003], [MS-PW-DYNAMIC]                     |
   | 139 - |                                                           |
   |   143 | [PW-OAM]                                                  |
   +=======+===========================================================+

         Table 2: PW Control (LDP) and MPLS-TP Requirements Table






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5.3.  Anticipated MPLS-TP-Related Extensions

   Existing control protocol and procedures will be reused as much as
   possible to support MPLS-TP.  However, when using PWs in MPLS-TP, a
   set of new requirements is defined that may require extensions of the
   existing control mechanisms.  This section clarifies the areas where
   extensions are needed based on the requirements that are related to
   the PW control plane and documented in [RFC5654].

   Table 2 lists how requirements defined in [RFC5654] are expected to
   be addressed.

   The baseline requirement for extensions to support transport
   applications is that any new mechanisms and capabilities must be able
   to interoperate with existing IETF MPLS [RFC3031] and IETF PWE3
   [RFC3985] control and data planes where appropriate.  Hence,
   extensions of the PW control plane must be in-line with the
   procedures defined in [RFC4447], [RFC6073], and [MS-PW-DYNAMIC].

5.3.1.  Extensions to Support Out-of-Band PW Control

   For MPLS-TP, it is required that the data and control planes can be
   both logically and physically separated.  That is, the PW control
   plane must be able to operate out-of-band (OOB).  This separation
   ensures, among other things, that in the case of control-plane
   failures the data plane is not affected and can continue to operate
   normally.  This was not a design requirement for the current PW
   control plane.  However, due to the PW concept, i.e., PWs are
   connecting logical entities ('forwarders'), and the operation of the
   PW control protocol, i.e., only edge PE nodes (T-PE, S-PE) take part
   in the signaling exchanges: moving T-LDP out-of-band seems to be,
   theoretically, a straightforward exercise.

   In fact, as a strictly local matter, ensuring that targeted LDP
   (T-LDP) uses out-of-band signaling requires only that the local
   implementation is configured in such a way that reachability for a
   target LSR address is via the out-of-band channel.

   More precisely, if IP addressing is used in the MPLS-TP control
   plane, then T-LDP addressing can be maintained, although all
   addresses will refer to control-plane entities.  Both the PWid
   Forwarding Equivalence Class (FEC) and Generalized PWid FEC Elements
   can possibly be used in an OOB case as well.  (Detailed evaluation is
   outside the scope of this document.)  The PW label allocation and
   exchange mechanisms should be reused without change.






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RFC 6373            MPLS-TP Control Plane Framework       September 2011


5.3.2.  Support for Explicit Control of PW-to-LSP Binding

   Binding a PW to an LSP, or PW segments to LSPs, is left to nodes
   acting as T-PEs and S-PEs or a control-plane entity that may be the
   same one signaling the PW.  However, an extension of the PW signaling
   protocol is required to allow the LSR at the signal initiation end to
   inform the targeted LSR (at the signal termination end) to which LSP
   the resulting PW is to be bound, in the event that more than one such
   LSP exists and the choice of LSPs is important to the service being
   setup (for example, if the service requires co-routed bidirectional
   paths).  This is also particularly important to support transport
   path (symmetric and asymmetric) bandwidth requirements.

   For transport services, MPLS-TP requires support for bidirectional
   traffic that follows congruent paths.  Currently, each direction of a
   PW or a PW segment is bound to a unidirectional LSP that extends
   between two T-PEs, two S-PEs, or a T-PE and an S-PE.  The
   unidirectional LSPs in both directions are not required to follow
   congruent paths, and therefore both directions of a PW may not follow
   congruent paths, i.e., they are associated bidirectional paths.  The
   only requirement in [RFC5659] is that a PW or a PW segment shares the
   same T-PEs in both directions and the same S-PEs in both directions.

   MPLS-TP imposes new requirements on the PW control plane, in
   requiring that both end points map the PW or PW segment to the same
   transport path for the case where this is an objective of the
   service.  When a bidirectional LSP is selected on one end to
   transport the PW, a mechanism is needed that signals to the remote
   end which LSP has been selected locally to transport the PW.  This
   would be accomplished by adding a new TLV to PW signaling.

   Note that this coincides with the gap identified for OOB support: a
   new mechanism is needed to allow explicit binding of a PW to the
   supporting transport LSP.

   The case of unidirectional transport paths may also require
   additional protocol mechanisms, as today's PWs are always
   bidirectional.  One potential approach for providing a unidirectional
   PW-based transport path is for the PW to associate different
   (asymmetric) bandwidths in each direction, with a zero or minimal
   bandwidth for the return path.  This approach is consistent with
   Section 3.8.2 of [RFC5921] but does not address P2MP paths.

5.3.3.  Support for Dynamic Transfer of PW Control/Ownership

   In order to satisfy requirement 47 (as defined in Section 2), it will
   be necessary to specify methods for transfer of PW ownership from the
   management to the control plane (and vice versa).



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RFC 6373            MPLS-TP Control Plane Framework       September 2011


5.3.4.  Interoperable Support for PW/LSP Resource Allocation

   Transport applications may require resource guarantees.  For such
   transport LSPs, resource reservation mechanisms are provided via
   RSVP-TE and the use of Diffserv.  If multiple PWs are multiplexed
   into the same transport LSP resources, contention may occur.
   However, local policy at PEs should ensure proper resource sharing
   among PWs mapped into a resource-guaranteed LSP.  In the case of
   MS-PWs, signaling carries the PW traffic parameters [MS-PW-DYNAMIC]
   to enable admission control of a PW segment over a resource-
   guaranteed LSP.

   In conjunction with explicit PW-to-LSP binding, existing mechanisms
   may be sufficient; however, this needs to be verified in detailed
   evaluation.

5.3.5.  Support for PW Protection and PW OAM Configuration

   Many of the requirements listed in Section 2 are intended to support
   connectivity and performance monitoring (grouped together as OAM), as
   well as protection conformant with the transport services model.

   In general, protection of MPLS-TP transported services is provided by
   way of protection of transport LSPs.  PW protection requires that
   mechanisms be defined to support redundant pseudowires, including a
   mechanism already described above for associating such pseudowires
   with specific protected ("working" and "protection") LSPs.  Also
   required are definitions of local protection control functions, to
   include test/verification operations, and protection status signals
   needed to ensure that PW termination points are in agreement as to
   which of a set of redundant pseudowires are in use for which
   transport services at any given point in time.

   Much of this work is currently being done in documents [PW-RED] and
   [PW-REDB] that define, respectively, how to establish redundant
   pseudowires and how to indicate which is in use.  Additional work may
   be required.

   Protection switching may be triggered manually by the operator, or as
   a result of loss of connectivity (detected using the mechanisms of
   [RFC5085] and [RFC5586]), or service degradation (detected using
   mechanisms yet to be defined).

   Automated protection switching is just one of the functions for which
   a transport service requires OAM.  OAM is generally referred to as
   either "proactive" or "on-demand", where the distinction is whether a
   specific OAM tool is being used continuously over time (for the
   purpose of detecting a need for protection switching, for example) or



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   is only used -- either a limited number of times or over a short
   period of time -- when explicitly enabled (for diagnostics, for
   example).

   PW OAM currently consists of connectivity verification defined by
   [RFC5085].  Work is currently in progress to extend PW OAM to include
   bidirectional forwarding detection (BFD) in [RFC5885], and work has
   begun on extending BFD to include performance-related monitor
   functions.

5.3.6.  Client-Layer and Cross-Provider Interfaces to PW Control

   Additional work is likely to be required to define consistent access
   by a client-layer network, as well as between provider networks, to
   control information available to each type of network, for example,
   about the topology of an MS-PW.  This information may be required by
   the client-layer network in order to provide hints that may help to
   avoid establishment of fate-sharing alternate paths.  Such work will
   need to fit within the ASON architecture; see requirement 38 above.

5.4.  ASON Architecture Considerations

   MPLS-TP PWs are always transported using LSPs, and these LSPs will
   either have been statically provisioned or signaled using GMPLS.

   For LSPs signaled using the MPLS-TP LSP control plane (GMPLS),
   conformance with the ASON architecture is as described in Section 1.2
   ("Basic Approach"), bullet 4, of this framework document.

   As discussed above in Section 5.3, there are anticipated extensions
   in the following areas that may be related to ASON architecture:

      - PW-to-LSP binding (Section 5.3.2)
      - PW/LSP resource allocation (Section 5.3.4)
      - PW protection and OAM configuration (Section 5.3.5)
      - Client-layer interfaces for PW control (Section 5.3.6)

   This work is expected to be consistent with ASON architecture and may
   require additional specification in order to achieve this goal.

6.  Security Considerations

   This document primarily describes how existing mechanisms can be used
   to meet the MPLS-TP control-plane requirements.  The documents that
   describe each mechanism contain their own security considerations
   sections.  For a general discussion on MPLS- and GMPLS-related





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RFC 6373            MPLS-TP Control Plane Framework       September 2011


   security issues, see the MPLS/GMPLS security framework [RFC5920].  As
   mentioned above in Section 2.4, there are no specific MPLS-TP
   control-plane security requirements.

   This document also identifies a number of needed control-plane
   extensions.  It is expected that the documents that define such
   extensions will also include any appropriate security considerations.

7.  Acknowledgments

   The authors would like to acknowledge the contributions of Yannick
   Brehon, Diego Caviglia, Nic Neate, Dave Mcdysan, Dan Frost, and Eric
   Osborne to this work.  We also thank Dan Frost in his help responding
   to Last Call comments.

8.  References

8.1.  Normative References

   [RFC2210]  Wroclawski, J., "The Use of RSVP with IETF Integrated
              Services", RFC 2210, September 1997.

   [RFC2211]  Wroclawski, J., "Specification of the Controlled-Load
              Network Element Service", RFC 2211, September 1997.

   [RFC2212]  Shenker, S., Partridge, C., and R. Guerin, "Specification
              of Guaranteed Quality of Service", RFC 2212, September
              1997.

   [RFC3031]  Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
              Label Switching Architecture", RFC 3031, January 2001.

   [RFC3209]  Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
              and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
              Tunnels", RFC 3209, December 2001.

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

   [RFC3473]  Berger, L., Ed., "Generalized Multi-Protocol Label
              Switching (GMPLS) Signaling Resource ReserVation Protocol-
              Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
              January 2003.

   [RFC3478]  Leelanivas, M., Rekhter, Y., and R. Aggarwal, "Graceful
              Restart Mechanism for Label Distribution Protocol", RFC
              3478, February 2003.



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RFC 6373            MPLS-TP Control Plane Framework       September 2011


   [RFC3630]  Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
              (TE) Extensions to OSPF Version 2", RFC 3630, September
              2003.

   [RFC4124]  Le Faucheur, F., Ed., "Protocol Extensions for Support of
              Diffserv-aware MPLS Traffic Engineering", RFC 4124, June
              2005.

   [RFC4202]  Kompella, K., Ed., and Y. Rekhter, Ed., "Routing
              Extensions in Support of Generalized Multi-Protocol Label
              Switching (GMPLS)", RFC 4202, October 2005.

   [RFC4203]  Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions
              in Support of Generalized Multi-Protocol Label Switching
              (GMPLS)", RFC 4203, October 2005.

   [RFC4206]  Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP)
              Hierarchy with Generalized Multi-Protocol Label Switching
              (GMPLS) Traffic Engineering (TE)", RFC 4206, October 2005.

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

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

   [RFC4448]  Martini, L., Ed., Rosen, E., El-Aawar, N., and G. Heron,
              "Encapsulation Methods for Transport of Ethernet over MPLS
              Networks", RFC 4448, April 2006.

   [RFC4842]  Malis, A., Pate, P., Cohen, R., Ed., and D. Zelig,
              "Synchronous Optical Network/Synchronous Digital Hierarchy
              (SONET/SDH) Circuit Emulation over Packet (CEP)", RFC
              4842, April 2007.

   [RFC4863]  Martini, L. and G. Swallow, "Wildcard Pseudowire Type",
              RFC 4863, May 2007.

   [RFC4872]  Lang, J., Ed., Rekhter, Y., Ed., and D. Papadimitriou,
              Ed., "RSVP-TE Extensions in Support of End-to-End
              Generalized Multi-Protocol Label Switching (GMPLS)
              Recovery", RFC 4872, May 2007.

   [RFC4873]  Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel,
              "GMPLS Segment Recovery", RFC 4873, May 2007.




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RFC 6373            MPLS-TP Control Plane Framework       September 2011


   [RFC4929]  Andersson, L., Ed., and A. Farrel, Ed., "Change Process
              for Multiprotocol Label Switching (MPLS) and Generalized
              MPLS (GMPLS) Protocols and Procedures", BCP 129, RFC 4929,
              June 2007.

   [RFC4974]  Papadimitriou, D. and A. Farrel, "Generalized MPLS (GMPLS)
              RSVP-TE Signaling Extensions in Support of Calls", RFC
              4974, August 2007.

   [RFC5063]  Satyanarayana, A., Ed., and R. Rahman, Ed., "Extensions to
              GMPLS Resource Reservation Protocol (RSVP) Graceful
              Restart", RFC 5063, October 2007.

   [RFC5151]  Farrel, A., Ed., Ayyangar, A., and JP. Vasseur, "Inter-
              Domain MPLS and GMPLS Traffic Engineering -- Resource
              Reservation Protocol-Traffic Engineering (RSVP-TE)
              Extensions", RFC 5151, February 2008.

   [RFC5287]  Vainshtein, A. and Y(J). Stein, "Control Protocol
              Extensions for the Setup of Time-Division Multiplexing
              (TDM) Pseudowires in MPLS Networks", RFC 5287, August
              2008.

   [RFC5305]  Li, T. and H. Smit, "IS-IS Extensions for Traffic
              Engineering", RFC 5305, October 2008.

   [RFC5307]  Kompella, K., Ed., and Y. Rekhter, Ed., "IS-IS Extensions
              in Support of Generalized Multi-Protocol Label Switching
              (GMPLS)", RFC 5307, October 2008.

   [RFC5316]  Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in
              Support of Inter-Autonomous System (AS) MPLS and GMPLS
              Traffic Engineering", RFC 5316, December 2008.

   [RFC5392]  Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in
              Support of Inter-Autonomous System (AS) MPLS and GMPLS
              Traffic Engineering", RFC 5392, January 2009.

   [RFC5467]  Berger, L., Takacs, A., Caviglia, D., Fedyk, D., and J.
              Meuric, "GMPLS Asymmetric Bandwidth Bidirectional Label
              Switched Paths (LSPs)", RFC 5467, March 2009.

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

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



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RFC 6373            MPLS-TP Control Plane Framework       September 2011


   [RFC5860]  Vigoureux, M., Ed., Ward, D., Ed., and M. Betts, Ed.,
              "Requirements for Operations, Administration, and
              Maintenance (OAM) in MPLS Transport Networks", RFC 5860,
              May 2010.

   [RFC5921]  Bocci, M., Ed., Bryant, S., Ed., Frost, D., Ed., Levrau,
              L., and L. Berger, "A Framework for MPLS in Transport
              Networks", RFC 5921, July 2010.

   [RFC5960]  Frost, D., Ed., Bryant, S., Ed., and M. Bocci, Ed., "MPLS
              Transport Profile Data Plane Architecture", RFC 5960,
              August 2010.

   [RFC6370]  Bocci, M., Swallow, G., and E. Gray, "MPLS Transport
              Profile (MPLS-TP) Identifiers", RFC 6370, September 2011.

   [RFC6371]  Busi, I., Ed., and D. Allan, Ed., "Operations,
              Administration, and Maintenance Framework for MPLS-Based
              Transport Networks", RFC 6371, September 2011.

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

8.2.  Informative References

   [CCAMP-OAM-EXT]
              Bellagamba, E., Ed., Andersson, L., Ed., Skoldstrom, P.,
              Ed., Ward, D., and A. Takacs, "Configuration of Pro-Active
              Operations, Administration, and Maintenance (OAM)
              Functions for MPLS-based Transport Networks using RSVP-
              TE", Work in Progress, July 2011.

   [CCAMP-OAM-FWK]
              Takacs, A., Fedyk, D., and J. He, "GMPLS RSVP-TE
              extensions for OAM Configuration", Work in Progress, July
              2011.

   [GMPLS-PS] Takacs, A., Fondelli, F., and B. Tremblay, "GMPLS RSVP-TE
              Recovery Extension for data plane initiated reversion and
              protection timer signalling", Work in Progress, April
              2011.

   [ITU.G8080.2006]
              International Telecommunication Union, "Architecture for
              the automatically switched optical network (ASON)", ITU-T
              Recommendation G.8080, June 2006.




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RFC 6373            MPLS-TP Control Plane Framework       September 2011


   [ITU.G8080.2008]
              International Telecommunication Union, "Architecture for
              the automatically switched optical network (ASON)
              Amendment 1", ITU-T Recommendation G.8080 Amendment 1,
              March 2008.

   [MS-PW-DYNAMIC]
              Martini, L., Ed., Bocci, M., Ed., and F. Balus, Ed.,
              "Dynamic Placement of Multi Segment Pseudowires", Work in
              Progress, July 2011.

   [NO-PHP]   Ali, z., et al, "Non Penultimate Hop Popping Behavior and
              out-of-band mapping for RSVP-TE Label Switched Paths",
              Work in Progress, August 2011.

   [PW-OAM]   Zhang, F., Ed., Wu, B., Ed., and E. Bellagamba, Ed., "
              Label Distribution Protocol Extensions for Proactive
              Operations, Administration and Maintenance Configuration
              of Dynamic MPLS Transport Profile PseudoWire", Work in
              Progress, August 2011.

   [PW-P2MPE] Aggarwal, R. and F. Jounay, "Point-to-Multipoint Pseudo-
              Wire Encapsulation", Work in Progress, March 2010.

   [PW-P2MPR] Jounay, F., Ed., Kamite, Y., Heron, G., and M. Bocci,
              "Requirements and Framework for Point-to-Multipoint
              Pseudowire", Work in Progress, July 2011.

   [PW-RED]   Muley, P., Ed., Aissaoui, M., Ed., and M. Bocci,
              "Pseudowire Redundancy", Work in Progress, July 2011.

   [PW-REDB]  Muley, P., Ed., and M. Aissaoui, Ed., "Preferential
              Forwarding Status Bit", Work in Progress, March 2011.

   [RFC3270]  Le Faucheur, F., Wu, L., Davie, B., Davari, S., Vaananen,
              P., Krishnan, R., Cheval, P., and J. Heinanen, "Multi-
              Protocol Label Switching (MPLS) Support of Differentiated
              Services", RFC 3270, May 2002.

   [RFC3468]  Andersson, L. and G. Swallow, "The Multiprotocol Label
              Switching (MPLS) Working Group decision on MPLS signaling
              protocols", RFC 3468, February 2003.

   [RFC3472]  Ashwood-Smith, P., Ed., and L. Berger, Ed., "Generalized
              Multi-Protocol Label Switching (GMPLS) Signaling
              Constraint-based Routed Label Distribution Protocol (CR-
              LDP) Extensions", RFC 3472, January 2003.




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RFC 6373            MPLS-TP Control Plane Framework       September 2011


   [RFC3477]  Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links
              in Resource ReSerVation Protocol - Traffic Engineering
              (RSVP-TE)", RFC 3477, January 2003.

   [RFC3812]  Srinivasan, C., Viswanathan, A., and T. Nadeau,
              "Multiprotocol Label Switching (MPLS) Traffic Engineering
              (TE) Management Information Base (MIB)", RFC 3812, June
              2004.

   [RFC3813]  Srinivasan, C., Viswanathan, A., and T. Nadeau,
              "Multiprotocol Label Switching (MPLS) Label Switching
              Router (LSR) Management Information Base (MIB)", RFC 3813,
              June 2004.

   [RFC3945]  Mannie, E., Ed., "Generalized Multi-Protocol Label
              Switching (GMPLS) Architecture", RFC 3945, October 2004.

   [RFC3985]  Bryant, S., Ed., and P. Pate, Ed., "Pseudo Wire Emulation
              Edge-to-Edge (PWE3) Architecture", RFC 3985, March 2005.

   [RFC4139]  Papadimitriou, D., Drake, J., Ash, J., Farrel, A., and L.
              Ong, "Requirements for Generalized MPLS (GMPLS) Signaling
              Usage and Extensions for Automatically Switched Optical
              Network (ASON)", RFC 4139, July 2005.

   [RFC4201]  Kompella, K., Rekhter, Y., and L. Berger, "Link Bundling
              in MPLS Traffic Engineering (TE)", RFC 4201, October 2005.

   [RFC4208]  Swallow, G., Drake, J., Ishimatsu, H., and Y. Rekhter,
              "Generalized Multiprotocol Label Switching (GMPLS) User-
              Network Interface (UNI): Resource ReserVation Protocol-
              Traffic Engineering (RSVP-TE) Support for the Overlay
              Model", RFC 4208, October 2005.

   [RFC4258]  Brungard, D., Ed., "Requirements for Generalized Multi-
              Protocol Label Switching (GMPLS) Routing for the
              Automatically Switched Optical Network (ASON)", RFC 4258,
              November 2005.

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

   [RFC4426]  Lang, J., Ed., Rajagopalan, B., Ed., and D. Papadimitriou,
              Ed., "Generalized Multi-Protocol Label Switching (GMPLS)
              Recovery Functional Specification", RFC 4426, March 2006.





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RFC 6373            MPLS-TP Control Plane Framework       September 2011


   [RFC4427]  Mannie, E., Ed., and D. Papadimitriou, Ed., "Recovery
              (Protection and Restoration) Terminology for Generalized
              Multi-Protocol Label Switching (GMPLS)", RFC 4427, March
              2006.

   [RFC4553]  Vainshtein, A., Ed., and YJ. Stein, Ed., "Structure-
              Agnostic Time Division Multiplexing (TDM) over Packet
              (SAToP)", RFC 4553, June 2006.

   [RFC4618]  Martini, L., Rosen, E., Heron, G., and A. Malis,
              "Encapsulation Methods for Transport of PPP/High-Level
              Data Link Control (HDLC) over MPLS Networks", RFC 4618,
              September 2006.

   [RFC4619]  Martini, L., Ed., Kawa, C., Ed., and A. Malis, Ed.,
              "Encapsulation Methods for Transport of Frame Relay over
              Multiprotocol Label Switching (MPLS) Networks", RFC 4619,
              September 2006.

   [RFC4655]  Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
              Computation Element (PCE)-Based Architecture", RFC 4655,
              August 2006.

   [RFC4783]  Berger, L., Ed., "GMPLS - Communication of Alarm
              Information", RFC 4783, December 2006.

   [RFC4802]  Nadeau, T., Ed., and A. Farrel, Ed., "Generalized
              Multiprotocol Label Switching (GMPLS) Traffic Engineering
              Management Information Base", RFC 4802, February 2007.

   [RFC4803]  Nadeau, T., Ed., and A. Farrel, Ed., "Generalized
              Multiprotocol Label Switching (GMPLS) Label Switching
              Router (LSR) Management Information Base", RFC 4803,
              February 2007.

   [RFC4816]  Malis, A., Martini, L., Brayley, J., and T. Walsh,
              "Pseudowire Emulation Edge-to-Edge (PWE3) Asynchronous
              Transfer Mode (ATM) Transparent Cell Transport Service",
              RFC 4816, February 2007.

   [RFC4875]  Aggarwal, R., Ed., Papadimitriou, D., Ed., and S.
              Yasukawa, Ed., "Extensions to Resource Reservation
              Protocol - Traffic Engineering (RSVP-TE) for Point-to-
              Multipoint TE Label Switched Paths (LSPs)", RFC 4875, May
              2007.






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

   [RFC5036]  Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
              "LDP Specification", RFC 5036, October 2007.

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

   [RFC5145]  Shiomoto, K., Ed., "Framework for MPLS-TE to GMPLS
              Migration", RFC 5145, March 2008.

   [RFC5440]  Vasseur, JP., Ed., and JL. Le Roux, Ed., "Path Computation
              Element (PCE) Communication Protocol (PCEP)", RFC 5440,
              March 2009.

   [RFC5493]  Caviglia, D., Bramanti, D., Li, D., and D. McDysan,
              "Requirements for the Conversion between Permanent
              Connections and Switched Connections in a Generalized
              Multiprotocol Label Switching (GMPLS) Network", RFC 5493,
              April 2009.

   [RFC5659]  Bocci, M. and S. Bryant, "An Architecture for Multi-
              Segment Pseudowire Emulation Edge-to-Edge", RFC 5659,
              October 2009.

   [RFC5787]  Papadimitriou, D., "OSPFv2 Routing Protocols Extensions
              for Automatically Switched Optical Network (ASON)
              Routing", RFC 5787, March 2010.

   [RFC5852]  Caviglia, D., Ceccarelli, D., Bramanti, D., Li, D., and S.
              Bardalai, "RSVP-TE Signaling Extension for LSP Handover
              from the Management Plane to the Control Plane in a GMPLS-
              Enabled Transport Network", RFC 5852, April 2010.

   [RFC5884]  Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
              "Bidirectional Forwarding Detection (BFD) for MPLS Label
              Switched Paths (LSPs)", RFC 5884, June 2010.

   [RFC5885]  Nadeau, T., Ed., and C. Pignataro, Ed., "Bidirectional
              Forwarding Detection (BFD) for the Pseudowire Virtual
              Circuit Connectivity Verification (VCCV)", RFC 5885, June
              2010.

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



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   [RFC5951]  Lam, K., Mansfield, S., and E. Gray, "Network Management
              Requirements for MPLS-based Transport Networks", RFC 5951,
              September 2010.

   [RFC6001]  Papadimitriou, D., Vigoureux, M., Shiomoto, K., Brungard,
              D., and JL. Le Roux, "Generalized MPLS (GMPLS) Protocol
              Extensions for Multi-Layer and Multi-Region Networks
              (MLN/MRN)", RFC 6001, October 2010.

   [RFC6073]  Martini, L., Metz, C., Nadeau, T., Bocci, M., and M.
              Aissaoui, "Segmented Pseudowire", RFC 6073, January 2011.

   [RFC6107]  Shiomoto, K., Ed., and A. Farrel, Ed., "Procedures for
              Dynamically Signaled Hierarchical Label Switched Paths",
              RFC 6107, February 2011.

   [RFC6215]  Bocci, M., Levrau, L., and D. Frost, "MPLS Transport
              Profile User-to-Network and Network-to-Network
              Interfaces", RFC 6215, April 2011.

   [TE-MIB]   Miyazawa, M., Otani, T., Kumaki, K., and T. Nadeau,
              "Traffic Engineering Database Management Information Base
              in support of MPLS-TE/GMPLS", Work in Progress, July 2011.

   [TP-MIB]   King, D., Ed., and M. Venkatesan, Ed., "Multiprotocol
              Label Switching Transport Profile (MPLS-TP) MIB-based
              Management Overview", Work in Progress, August 2011.

   [TP-P2MP-FWK]
              Frost, D., Ed., Bocci, M., Ed., and L. Berger, Ed., "A
              Framework for Point-to-Multipoint MPLS in Transport
              Networks", Work in Progress, July 2011.

   [TP-RING]  Weingarten, Y., Ed., "MPLS-TP Ring Protection", Work in
              Progress, June 2011

9.  Contributing Authors

   Attila Takacs
   Ericsson
   1. Laborc u.
   Budapest 1037
   HUNGARY
   EMail: attila.takacs@ericsson.com

   Martin Vigoureux
   Alcatel-Lucent
   EMail: martin.vigoureux@alcatel-lucent.fr



Andersson, et al.             Informational                    [Page 56]

RFC 6373            MPLS-TP Control Plane Framework       September 2011


   Elisa Bellagamba
   Ericsson
   Farogatan, 6
   164 40, Kista, Stockholm
   SWEDEN
   EMail: elisa.bellagamba@ericsson.com

Authors' Addresses

   Loa Andersson (editor)
   Ericsson
   Phone: +46 10 717 52 13
   EMail: loa.andersson@ericsson.com

   Lou Berger (editor)
   LabN Consulting, L.L.C.
   Phone: +1-301-468-9228
   EMail: lberger@labn.net

   Luyuan Fang (editor)
   Cisco Systems, Inc.
   111 Wood Avenue South
   Iselin, NJ 08830
   USA
   EMail: lufang@cisco.com

   Nabil Bitar (editor)
   Verizon
   60 Sylvan Road
   Waltham, MA 02451
   USA
   EMail: nabil.n.bitar@verizon.com

   Eric Gray (editor)
   Ericsson
   900 Chelmsford Street
   Lowell, MA 01851
   USA
   Phone: +1 978 275 7470
   EMail: Eric.Gray@Ericsson.com











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