Network Working Group                              Seisho Yasukawa (NTT)
Internet Draft                                                    Editor
Category: Standards Track
Expiration Date: June August 2004                                  January                                  March 2004

       Requirements for Point to Multipoint extension to RSVP-TE
               <draft-ietf-mpls-p2mp-requirement-01.txt>
               <draft-ietf-mpls-p2mp-requirement-02.txt>

Status of this Memo

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Abstract

   This document presents a basic set of requirements for Point-to-Multipoint
   (P2MP) Point-to-
   Multipoint(P2MP) Traffic Engineering (TE) extensions to Multiprotocol
   Label Switching (MPLS). It specifies functional requirements for
   RSVP-TE in order to deliver P2MP applications over a MPLS TE
   infrastructure. It is intended that potential solutions, solutions that specify RSVP-TE
   procedures for P2MP TE LSP setup, use setup satisfy these requirements as a guideline. It requirements. There is
   not intended
   no intent to specify solution specific details in this document.

   It is intended that the requirements presented in this document are
   not limited to the requirements of packet switched networks, but also
   encompass the requirements of L2SC, TDM, lambda and port switching
   networks managed by Generalized MPLS (GMPLS) protocols. Protocol
   solutions developed to meet the requirements set out in this document
   must be equally applicable to MPLS and GMPLS.

   Table of Contents

   1. Introduction .................................................. 4
   2. Definitions ................................................... 5
      2.1 Acronyms .................................................. 5
      2.2 Terminology ............................................... 5
      2.3 Conventions ............................................... 6 7
   3. Problem statements ............................................ 7
      3.1 Motivation ................................................ 7
      3.2 Requirements overview ..................................... 7 8
   4. Application Specific Requirements ............................. 9 .............................10
      4.1 P2MP tunnel for IP multicast data ......................... 9 .........................10
      4.2 P2MP TE backbone network for IP multicast network .........10 .........11
      4.3 Layer 2 Multicast Over MPLS ...............................11 ...............................12
      4.4 VPN multicast network .....................................12 .....................................13
      4.5 GMPLS network .............................................13 .............................................14
   5. Detailed requirements for P2MP TE extensions ..................13 ..................14
      5.1 P2MP LSP tunnels ..........................................13 ..........................................14
      5.2 P2MP explicit routing .....................................14 .....................................15
      5.3 Explicit Path Loose Hops and Widely Scoped Abstract Nodes .15 .16
      5.4 P2MP TE LSP establishment, teardown, and modification
          mechanisms ................................................16 ................................................17
      5.5 Failure Reporting and Error Recovery ......................16 ......................17
      5.6 Record route of P2MP TE LSP tunnels .......................17 .......................18
      5.7 Call Admission Control (CAC) and QoS control mechanism
          of P2MP TE LSP tunnels ....................................18
      5.8 Reoptimization of P2MP TE LSP .............................18 .............................19
      5.9 IPv4/IPv6 support .........................................19
      5.10 P2MP MPLS Label ..........................................19 ..........................................20
      5.11 Routing advertisement of P2MP capability .................19 .................20
      5.12 Multi-Area/AS LSP ........................................19 ........................................20
      5.13 P2MP MPLS management .....................................20 OAM ............................................20
      5.14 Scalability ..............................................20 ..............................................21
      5.15 Backwards Compatibility ..................................20 ..................................21
      5.16 GMPLS ....................................................21 ....................................................22
      5.17 Requirements for Hierarchical P2MP TE LSPs ...............21 ...............22
      5.18 P2MP Crankback routing ...................................22 ...................................23
   6. Security Considerations........................................22 Considerations........................................23
   7. Acknowledgements ..............................................22 ..............................................23
   8. References ....................................................22 ....................................................23
      8.1 Normative References ......................................22 ......................................23
      8.2 Informational References ..................................23 ..................................24
   9. Author's Addresses ............................................24 Editor's Address ..............................................26
  10. Authors' Addresses ............................................26
  11. Intellectual Property Consideration ...........................26
  11. ...........................27
      11.1 IPR Disclosure Acknowledgement ...........................28
  12. Full Copyright Statement ......................................26 ......................................28

1. Introduction

   Existing MPLS Traffic Engineering (MPLS-TE) allows for strict QoS
   guarantees, resources optimization, and fast failure recovery recovery, but is
   limited to P2P applications. There are P2MP applications like Content
   Distribution, Interactive Multimedia and VPN multicast that would
   also benefit from these TE capabilities. This clearly motivates for
   enhancement
   enhancements of the base MPLS-TE tool box in order to support P2MP
   applications.

   This document presents a set of requirements for Point-to-Multipoint
   (P2MP) Traffic Engineering (TE) extensions to Multiprotocol Label
   Switching (MPLS). It specifies functional requirements for RSVP-TE
   [RFC3209] in order to deliver P2MP applications over a MPLS TE.

   It is intended that potential solutions, that specify RSVP-TE
   procedures and extensions for P2MP TE LSP setup, use satisfy these requirements as a
   guideline.
   requirements. It is not intended to specify solution specific details
   in this document.

   It is intended that the requirements presented in this document are
   not limited to the requirements of packet switched networks, but also
   encompass the requirements of TDM, lambda and port switching networks
   managed by Generalized MPLS (GMPLS) protocols. Protocol solutions
   developed to meet the requirements set out in this document must be
   equally applicable to MPLS and GMPLS.

   Content Distribution (CD), Interactive multi-media (IMM), and VPN
   multicast are applications that are best supported with multicast
   capabilities. One possible way to map P2MP flows onto LSPs in a MPLS
   network is to setup multiple P2P TE LSPs, one to each of the required
   egress LSRs. This requires replicating incoming packets to all the
   P2P LSPs at the ingress LSR to accommodate multipoint communication.
   This is sub-optimal. It places the replication burden on the ingress
   LSR and hence has very poor scaling characteristics. It also wastes
   bandwidth resources, memory and MPLS (e.g. label) resources in the
   network.

   Hence, to provide TE for a P2MP application in an efficient manner
   in a large-scale environment, P2MP TE mechanisms are required
   specifically to support P2MP TE LSPs. Existing MPLS TE mechanisms
   [RFC3209] do not support P2MP TE LSPs so new mechanisms must be
   developed.

   This should be achieved without running a multicast routing protocol
   in the network core core, and with maximum re-use of the existing MPLS
   protocols
   protocols: in particular particular, MPLS Traffic Engineering.

   A P2MP TE LSP will be set up with TE constraints and will allow
   efficient packet or data replication at various branching points in
   the network. RSVP-TE will be used for setting up a P2MP TE LSP with
   enhancements to existing P2P TE LSP procedures. The P2MP TE LSP setup
   mechanism will include the ability to add/remove receivers to/from an
   existing P2MP TE LSP.

   Moreover, multicast traffic cannot currently benefit from P2P TE LSP.
   LSPs. Hence, CAC for P2P TE LSP cannot take into account the
   bandwidth used for multicast traffic. P2MP TE will allow to count the
   bandwidth used by unicast and multicast traffic to be counted by
   means of CAC.

   The problem statement is discussed in the following section. Section 3. This
   document discusses various applications that can use P2MP TE LSP.

   Detailed requirements for the setup of a P2MP MPLS TE LSP using
   RSVP-TE are described. Application specific requirements are also
   described.

2. Definitions

2.1 Acronyms

   P2P:

      Point-to-point

   P2MP:

      Point-to-multipoint

2.2 Terminology

   The reader is assumed to be familiar with the terminology in
   [RFC3031] and [RFC3209].

   P2MP TE LSP:

      A traffic engineered label switched path that has one unique
      ingress LSR (also referred to as the root) and more than one
      egress LSR (also referred to as the leaf).

   P2MP path: tree:

      The ordered set of LSRs and links that comprise the path of
      a P2MP TE LSP from its ingress LSR to all of its egress LSRs.

      This path may be viewed as a tree.

   sub-P2MP path: tree:

      A sub-P2MP path tree is a portion of a P2MP path tree starting at
      a particular LSR that is a member of the P2MP path tree and includes
      ALL downstream LSRs that are also members of the P2MP path.
      A sub-P2MP path may be viewed as a sub-tree. tree.

   P2P sub-LSP path: sub-LSP:

      The path from the ingress LSR to a particular egress LSR.

   ingress LSR:

      The LSR that is responsible for initiating the signaling messages
      that set up the P2MP TE LSP.

   egress LSR:

      One of potentially many destinations of the P2MP TE LSP. Egress
      LSRs may also be referred to as leaf nodes or leaves.

   bud LSR:

     An LSR that is an egress, but also has one or more directly
     connected downstream LSRs.

   branch LSR:

      An LSR that has more than one directly connected downstream LSR.

   graft LSR:

      An LSR that is already a member of the P2MP path tree and is in
      process of signaling a new sub-P2MP path. tree.

   prune LSR:

      An LSR that is already a member of the P2MP path tree and is in
      process of tearing down an existing sub-P2MP path. tree.

   P2MP-ID (Pid):

      The ID that can be used to map a set of P2P sub- LSPs to a
      particular P2MP LSP.

2.3 Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC2119 [5]. [RFC2119].

3. Problem Statement

3.1 Motivation

   Content Distribution (CD), Interactive multi-media (IMM), and VPN
   multicast are applications that are best supported with multicast
   capabilities.

   IP Multicast provides P2MP communication. However, there are no
   Traffic Engineering (TE) capabilities or QoS guarantees with existing
   IP multicast protocols. Note that Diff-serv (see [RFC2475],[RFC2597]
   and [RFC3246]) combined with IP multicast routing may not be
   sufficient for P2MP applications for many of the same reasons that
   it is not sufficient for unicast applications. Note also that
   multicast tree provided by existing IP multicast routing protocols
   are not optimal, which may lead to significant bandwidth wasting.
   TE and Constraint Based Routing, including Call Admission Control
   (CAC), explicit source routing and bandwidth reservation, is required
   to enable efficient resource optimization, strict QoS guarantees, and
   fast recovery around network failures.

   Furthermore there are no existing P2MP mechanisms for carrying
   layer 2 or SONET/SDH multicast traffic over MPLS. TE capabilities are
   desirable for both these applications.

   One possible solution would be to setup multiple P2P TE LSPs, one to
   each of the required egress LSRs. This requires replicating incoming
   traffic to all the P2P LSPs at the ingress LSR to accommodate
   multipoint communication. This is clearly sub-optimal. It places the
   replication burden on the ingress LSR and hence has very poor scaling
   characteristics. It also wastes bandwidth resources, memory and MPLS
   (e.g. label) resources in the network.

   Hence, to provide MPLS TE [RFC2702] for a P2MP application in an
   efficient manner in a large scale environment, P2MP TE mechanisms are
   required. Existing MPLS P2P TE mechanisms have to be enhanced to
   support P2MP TE LSP.

3.2. Requirements Overview

   This document is proposing states basic requirements for the setup of P2MP TE
   LSPs. This should be achieved without running a multicast routing
   protocol in the network core and with maximum re-use of the existing
   MPLS protocols. Note that the use of MPLS forwarding to carry the
   multicast traffic may also be useful in the context of some network
   design where it is being desired to avoid running some multicast
   routing protocol like PIM [PIM-SM] or BGP (which might be required
   for the use of PIM).

   A P2MP LSP will be set up with TE constraints and will allow
   efficient MPLS packet replication at various branching points in the
   network. RSVP-TE will be used for setting up a P2MP TE LSP with
   enhancements to existing P2P TE LSP procedures.

   The P2MP TE LSP setup mechanism will include the ability to
   add/remove egress LSRs to/from an existing P2MP TE LSP and should
   support all the TE LSP management procedures defined for P2P TE LSP
   (like the non disruptive rerouting - the so called "Make before
   break" procedure).

   The computation of P2MP TE paths trees is implementation dependent and is
   beyond the scope of the solutions that are built with this document
   as a guideline.

   The MPLS WG

   A separate document(s) will specify how to build P2MP TE LSPs. The
   usage of those solutions will be application dependent and is out of
   the scope of this draft. document. However, it is a requirement that those
   solutions be applicable to GMPLS as well as to MPLS so that only a
   single set of solutions are developed.

   Consider the following figure.

                         Source 1 (S1)
                               |
                             I-LSR1
                             |   |
                             |   |
            R2----E-LSR3--LSR1   LSR2---E-LSR2--Receiver 1 (R1)
                             |   :
                  R3----E-LSR4   E-LSR5
                             |   :
                             |   :
                            R4   R5

                           Figure 1

   The figure above

   Figure 1 shows a single ingress (I-LSR1), and four egresses
   (E-LSR2, E-LSR3, E-LSR4 and E-LSR5). I-LSR1 is attached to a traffic
   source that is generating traffic for a P2MP application.
   Receivers:R1,
   Receivers R1, R2, R3 and R4 are attached to E-LSR2, E-LSR3 and
   E-LSR4.

   The following are the objectives that we wish to achieve: of P2MP LSP establishment and use.

      a) A P2MP TE LSP path tree which satisfies various
         constrains constraints is pre-determined pre-
         determined and supplied to ingress I-LSR1.

         Note that no assumption is made on whether the path tree is provided
         to I-LSR1 or computed by I-LSR1.

         Typical constraints are bandwidth requirements, resource class
         affinities, fast rerouting, preemption. There should not be any
         restriction on the possibility to support the set of
         constraints already defined for point to point TE LSPs. A new
         constraint may specify which LSRs should be used as branch
         points for the P2MP LSR in order to take into account some LSR
         capabilities or network constraints.

      b) A P2MP TE LSP is set up by means of RSVP-TE from I-LSR1 to
         E-LSR2, E-LSR3 and E-LSR4 using the path tree information.

      c) In this case, the branch LSR1 should replicate incoming packets
         or data and send them to E-LSR3 and E-LSR4.

      d) If a new receiver (R5) expresses an interest in receiving
         traffic, a new path tree is determined and a sub-P2MP path tree from
         LSR2 to E-LSR5 is grafted onto the P2MP path. tree. LSR2 becomes
         a branch LSR.

4. Application Specific Requirements

   This section describes some of the applications that P2MP MPLS
   TE is applicable to along with application specific requirements.

   The purpose of this section is not to mandate how P2MP TE LSPs must
   be used in certain application scenarios. Rather it is to illustrate
   some of the potential application scenarios so as to highlight
   the features and functions that any P2MP solution must provide in
   order to be of wide use and applicability. This section is not meant
   to be exhaustive exhaustive, and P2MP is not limited to the described
   applications.

4.1 P2MP TE LSP for IP multicast data

   One typical scenario is to use P2MP TE LSPs as P2MP tunnels carrying
   multicast data traffic (e.g. IP mcast). In this scenario, a P2MP TE
   LSP is established between an ingress LSR which supports
   IP multicast source and several egress LSRs which support several
   IP multicast receivers. Instead of using an IP multicast routing
   protocol in the network core, a P2MP TE LSP is established over
   the network and IP multicast data are tunneled from an ingress LSR
   node to multiple egress leaf LSRs with data replication at the
   branch LSRs in the network core. Figure 2 shows an example.

   Note that a P2MP TE LSP can be established over multiple areas/ASs
   and that the egress LSRs may deliver data into an IP multicast
   network.

                             Mcast Source
                                  |
               +---------------I-LSR0----------------+
               |                  |                  |
               |                LSR0            +----E-LSR2---R2
               |               /    \          /     |
     R1---E-LSR1---LSR2-----LSR1     LSR3----LSR4----E-LSR3---R3
               |             /        \        \     |
               |            /          \        +----E-LSR4---R4
               +-------B-LSR1---------B-LSR2---------+
               +-------- / ------++------ \ ---------+
               |         |       ||                  |
     R5---E-LSR5--------LSR5     || IPmcast Network  |
               |       /  \      ||                  |
               +-E-LSR6---E-LSR7-++----MR0--MR1------+
                   |        |           |    |
                   R6       R7          R8   R9

                              Figure 2

4.2  P2MP TE backbone network for IP multicast network

   P2MP TE LSPs are applicable in a backbone network to construct or
   support a multicast network(e.g. IPmcast network).

   The IP multicast access networks are interconnected by P2MP TE LSPs.
   A P2MP TE LSP is established from an ingress LSR which accommodates
   an IP multicast network that has a multicast source to multiple
   egress LSRs which each accommodate an IP multicast network.

   In this scenario, ingress/egress LSRs placed at the edge of multicast
   network must handle an IP multicast routing protocol. This means that
   the ingress/egress LSRs exchange IP multicast routing messages as
   neighbour routers. Figure 3 shows a network example of this scenario.

   A P2MP TE LSP is established from a I-LSR1 to E-LSR2, E-LSR3, E-LSR4
   and the ingress/egress LSR exchanges the multicast routing messages
   with each other.

   As specified in the section on the problem statement it should be
   possible for a solution to add/remove egress LSRs to/from the
   P2MP MPLS TE LSP. IP multicast group membership distribution between
   the egress LSRs may change frequently. This in turn may require a
   potential P2MP MPLS TE solution, that is suitable for IP multicast,
   to handle additions/deletions of egress LSRs with an appropriate
   reactiveness.

   It is recommended to support a message exchange mechanism on top of
   P2MP LSP setup mechanism to support multicast (S, G) Join/Leave.

   Though several schemes exist to handle this scenario, these are out
   of scope of this document. This document only describes requirements
   to setup a P2MP TE LSP.

                             Mcast Source
                                  |
                           +-----MR-----+
                           |      |     |
                           |     MR     |
                           +------|-----+
               +---------------I-LSR1----------------+
               |              // ||| \\              |
               |             //  |||  \\             |
               |            //  |LSR|  \\            |
               |        ___//____/|_____\\____       |
               |       /  //     |||     \\   \      |
               |       | //      |||      \\  |      |
               +-----E-LSR2----E-LSR3-----E-LSR4-----+
               +---- / ---++------|------++--- \ ----+
               |    |     ||      |      ||    |     |
          R1---MR---MR    ||      MR     ||    MR__  |
               |   /  \   ||     /  \    ||   /  \ \MR---R8
               +--MR--MR--++----MR--MR---++--MR--MR--+
                  |    |        |    |       |    |
                  R2   R3       R4   R5      R6   R7

                                Figure 3

4.3  Layer 2 Multicast Over MPLS

   Existing layer 2 networks offer multicast video services. These
   are typically carried using layer 2 NBMA technology such as ATM
   or layer 2 Broadcast Access technology such as Ethernet. It may be
   desirable to deliver these layer 2 multicast services over a
   converged MPLS infrastructure where P2MP TE LSPs are used instead.

   For instance, several SPs provision P2MP ATM VCs for TV/ADSL
   services. These P2MP VCs are setup between a video server and a set
   of ATM DSLAMs. Each channel is carried in a distinct P2MP VC. These
   VC maybe be routed independently, or may all be nested into a unique
   PVC, connecting the video sever to all DSLAMs.

   Such service could benefit from a P2MP MPLS-TE control plane. An
   option is to setup a permanent P2MP TE LSP between the video server
   and all DSLAMs, that would correspond to a PVC carrying all channel
   VCs. In this case each DSLAM receives all channels, even if there are
   no receivers that are registered for a given channel. This ensure
   fast zapping, but lead to significant bandwidth wasting.

   A second option is to setup a distinct P2MP TE LSP per channel. If a
   client, behind a DSLAM, zaps to a new channel, then the DSLAM has
   to be added to the P2MP TE LSP carrying this channel using a P2MP TE
   grafting procedure. Pruning procedure has to be used to remove a
   DSLAM from the P2MP TE LSP if it is not already egress LSR for that
   LSP because all the clients, behind the DSLAM, stop watching the
   channel.

4.4 VPN multicast network

   In this scenario, P2MP TE LSPs are utilized to construct a provider
   network which can deliver VPN multicast service(s) to its customers.

   A P2MP TE LSP is established between all the PE routers which
   accommodate the customer private network(s) that handle the IP
   multicast packets. Each PE router must handle a VPN instance.

   For example, in Layer3 VPNs like BGP/MPLS based IP VPNs
   [BGP/MPLS IP VPNs],
   [BGPMPLS-VPN], this means that each PE router must handle both
   private multicast VRF tables and common multicast routing and
   forwarding table.  And each PE router exchanges private multicast
   routing information between the corresponding PE routers. It is
   desirable that P2MP MPLS TE can be used for Layer3 VPN data
   transmission.

   Another example is a Layer2 VPN that supports multipoint
   LAN connectivity service. In an Ethernet network environment, IP
   multicast data is flooded to the appropriate Ethernet port(s).

   An Ethernet multipoint Layer2 VPN service provided by MPLS, this
   function is achieved by switching MPLS encapsulated frames towards
   the relevant PE nodes. But if existing P2P TE LSPs are used as
   tunnels between PEs, any ingress PE must duplicate the frames and
   send them to the corresponding PEs. This means the data stream is
   flooded just from the ingress PE, which will waste the provider's
   network resources.

   So, for Layer 2 VPNs that are required to support multicast traffic,
   it is desirable that P2MP MPLS TE LSPs are used for data transmission
   instead of P2P MPLS TE LSPs, contributing in turn to savings of
   network resources.

   This document does not set requirements for how multicast VPNs are
   provided, but it does set requirements for the function that must be
   available in P2MP MPLS solutions. Therefore, it is not a requirement
   that multicast VPNs utilize P2MP MPLS, but it is a requirement that
   P2MP MPLS solutions should be capable of supporting multicast VPNs.

4.5 GMPLS Networks

   GMPLS supports only P2P TE-LSPs just like MPLS. GMPLS enhances MPLS
   to support four new classes of interfaces: Layer-2 Switch Capable
   (L2SC), Time-Division Multiplex (TDM), Lambda Switch Capable (LSC)
   and Fiber-Switch Capable (FSC) in addition to Packet Switch Capable
   (PSC) already supported by MPLS. All of these interface classes have
   so far been limited to P2P TE LSPs (see [RFC 3473] and [RFC 3471]).

   The requirement for P2MP services for non-packet switch interfaces
   is similar to that for PSC interfaces. In particular, cable
   distribution services such as video distribution are prime candidates
   to use P2MP features. Therefore, it is a requirement that all the
   features/mechanisms (and protocol extensions) that will be defined to
   provide MPLS P2MP TE LSPs will be equally applicable to P2MP PSC and
   non-PSC TE-LSPs.

5. Detailed requirements for P2MP TE extensions

5.1 P2MP LSP tunnels

   The P2MP RSVP-TE extensions MUST be applicable to signaling LSPs
   of different traffic types. For example, it must MUST be possible to
   signal a P2MP TE LSP to carry any kind of payload being packet or
   non-packet based (including frame, cell, TDM un/structured, etc.)
   Carrying IP multicast or Ethernet traffic within a P2MP tunnel are
   typical examples.

   As with P2P MPLS technology [RFC3031], traffic is classified with a
   FEC in this extension. All packets which belong to a particular FEC
   and which travel from a particular node MUST follow the same P2MP
   path.
   tree.

   In order to scale to a large number of branches, P2MP TE LSPs should SHOULD
   be identified by a unique identifier (the P2MP ID or Pid) that is
   constant for the whole LSP regardless of the number of branches
   and/or leaves. Therefore, the identification of the P2MP session by
   its destination addresses is not adequate.

5.2 P2MP explicit routing

   Various optimizations in P2MP path tree formation need to be applied to
   meet various QoS requirements and operational constraints.

   Some P2MP applications may request a bandwidth guaranteed P2MP path tree
   which satisfies end-to-end delay requirements. And some operators
   may want to set up a cost minimum P2MP path tree by specifying branch LSRs
   explicitly.

   The P2MP TE solution therefore MUST provide a means of establishing
   arbitrary P2MP paths trees under the control of an external path tree
   computation process or path configuration process or dynamic path tree
   computation process located on the ingress LSR. Figure 4 shows two
   typical examples.

                A                                      A
                |                                    /   \
                B                                   B     C
                |                                  / \   / \
                C                                 D   E  F   G
                |                                / \ / \/ \ / \
    D--E*-F*-G*-H*-I*-J*-K*--L                  H  I J KL M N  O

         Steiner P2MP path tree                        SPF P2MP path tree

                Figure 4 Examples of P2MP TE LSP topology

   One example is Steiner[STEINER] the Steiner P2MP path tree (Cost minimum P2MP path). tree)
   [STEINER]. This P2MP path tree is suitable for constructing a cost minimum
   P2MP path. tree. To realize this P2MP path, tree, several intermediate LSRs must
   be both MPLS data terminating LSR LSRs and transit LSR (LSR LSRs (LSRs E, F, G, H,
   I, J, K, J and K in the figure 4). This means that the LSR LSRs must perform
   both label swapping and popping at the same time. Therefore, the P2MP
   TE solution MUST support a mechanism that can setup this kind of
   bud LSR between an ingress LSR and egress LSRs.

   Another example is a CSPF (Constraint Shortest Path Fast) P2MP path. tree.
   By some metric (which can be set upon any specific criteria like the
   delay, bandwidth, a combination of those), one can calculate a cost
   minimum P2MP path. tree. This P2MP path tree is suitable for carrying real time
   traffic.

   To support explicit setup of any reasonable P2MP path tree shape, a P2MP
   TE solution MUST support some form of explicit source-based control
   of the P2MP path tree which can explicitly include particular LSRs as
   branch nodes. This can be used by the ingress LSR to setup the P2MP
   TE LSP. Being implementation specific (more precisely dependent of on
   the data structure specific representation and its processing), the
   detailed method for controlling the P2MP TE LSP topology depends on
   how the control plane represents the P2MP TE LSP data plane entity.

   For instance, a P2MP TE LSP can be simply represented as a
   whole tree or by its individual branches.

   Here also, the effectiveness of the potential solutions is left outside
   the scope of this document. In any case, it is expected that this
   control must be driven by the ingress LSR.

5.3 Explicit Path Loose Hops and Widely Scoped Abstract Nodes

   A P2MP path tree is completely specified if all of the required
   branches and hops between a sender and leaf LSR are indicated.

   A P2MP path tree is partially specified if only a subset of intermediate
   branches and hops are indicated. This may be achieved using
   loose hops in the explicit path, or using widely scoped abstract
   nodes such as IPv4 prefixes shorter than 32 bits bits, or AS numbers.
   A partially specified P2MP path tree may be particularly useful in
   inter-area and inter-AS situations.

   Protocol solutions SHOULD include a way to specify loose
   hops and widely scoped abstract nodes in the explicit source-
   based control of the P2MP path tree as defined in the previous
   section. Where this support is provided, protocol solutions
   MUST allow downstream LSRs to apply further explicit
   control to the P2MP path tree to resolve a partially specified path tree
   into a (more) completely specified path. tree.

   Protocol solutions MUST allow the P2MP path tree to be completely
   specified at the ingress where sufficient information exists to allow
   the full path tree to be computed.

   In all cases, the egress nodes of the P2MP TE LSP must be fully
   specified.

   In case of path a tree being computed by some downstream LSRs (e.g. the
   case of hops specified as loose hops), the solution SHOULD MUST provide the
   ability for the ingress LSR of the P2MP TE LSP to learn the full
   P2MP path. tree. Note that this requirement may MAY be relaxed in some
   environment
   environments (e.g. Inter-AS) where confidentiality must be preserved.

5.4 P2MP TE LSP establishment, teardown, and modification mechanisms

   The P2MP TE solution must MUST support large scale P2MP TE LSPs
   establishment and teardown in a scalable manner.

   In addition to P2MP TE LSP establishment and teardown mechanism,
   it SHOULD implement partial P2MP path tree modification mechanism.

   For the purpose of adding sub-P2MP TE LSPs for to an existing P2MP TE
   LSP, the extension extensions SHOULD support a grafting mechanism. For the
   purpose of deleting a sub-P2MP TE LSPs from an existing P2MP TE
   LSP, the extension extensions SHOULD support a pruning mechanism.

   It is RECOMMENDED that these grafting and pruning operations do not
   cause any additional processing in nodes except along the path to the
   grafting and pruning node and its downstream nodes. Moreover, both
   grafting and pruning operations MUST not be traffic disruptive for
   the traffic currently forwarded along the P2MP path. tree.

5.5 Failure Reporting and Error Recovery

   Failure events may cause egress nodes or sub-P2MP LSPs to become
   detached from the P2MP TE LSP. These events must MUST be reported upstream
   as for a P2P LSP.

   The solution SHOULD provide recovery techniques such as protection
   and restoration allowing to recover recovery of any impacted sub-P2MP TE LSPs.
   In particular, it is required to a solution MUST provide fast protection mechanisms
   applicable to P2MP TE LSP similar to the solutions specified in [FRR]
   for P2P TE LSPs. Note also that no assumption is made on whether
   backup paths for P2MP TE LSPs should or should not be shared with P2P
   TE LSPs backup paths.

   A P2MP TE solution MUST support P2MP fast protection mechanism
   to handle P2MP applications sensitive to traffic disruption.

   The report of the failure of delivery to fewer than all of the egress
   nodes SHOULD NOT cause automatic teardown of the P2MP TE LSP.
   That is, while some egress nodes remain connected to the P2MP path tree it
   should be a matter of local policy at the ingress whether the P2MP
   LSP is retained.

   When all egress node nodes downstreams of a branch node have become
   disconnected from the P2MP path, tree, and the some branch node is unable
   to restore connectivity to any of them through recovery or protection
   mechanisms, the branch node MAY remove itself from the P2MP path. tree.
   Since the faults that severed the various downstream egress nodes
   from the P2MP path tree may be disparate, the branch node MUST report all
   such errors to its upstream neighbor. The ingress node can then
   decide to re-compute the path to that those particular egress node, nodes,
   around the failure point.

   Solutions MAY include the facility for transit LSRs and particularly
   branch nodes to recompute sub-P2MP paths trees to restore them after
   failures. In the event of successful repair, no error notification is notifications
   SHOULD NOT be reported to upstream nodes, but the new paths are
   reported if route recording is in use. Crankback requirements are
   discussed in
   [CRANKBACK]. Section 5.18.

5.6 Record route of P2MP TE LSP tunnels

   Being able to identify the established topology of P2MP TE LSP is
   very important for various purpose:Management, purposes such as management and operation
   of some local recovery mechanism mechanisms like Fast Reroute [FRR]. A network
   operator uses this information to manage P2MP TE LSP. LSPs. Therefore,
   topology information MUST be collected and updated after P2MP TE LSP
   establishment and modification process.

   For this purpose, the conventional Record Route mechanism is useful.
   As with other conventional mechanism, this information should be
   forwarded upstream towards the sender node. The P2MP TE solution MUST
   support a mechanism which can collect and update P2MP path tree topology
   information after P2MP LSP establishment and modification process.

   It is RECOMMENDED that those the information are is collected in a data
   format by which the sender node can recognize the P2MP path tree topology
   without involving some complicated data calculation process.

   The solution MUST support the recording of both outgoing interfaces
   or
   and node-id [NODE-ID].

5.7 Call Admission Control (CAC) and QoS Control mechanism
    of P2MP TE LSP tunnels

   P2MP TE LSP LSPs may share network resource with P2P TE LSP. LSPs. Therefore
   it is important to use CAC and QoS in the same way as P2P TE LSP LSPs
   for easy and scalable operation.

   In particular, it should be highlighted that because Multicast
   traffic cannot make use of point to point P2P TE LSP, multicast traffic cannot be
   easily taken into account by point to point in
   order to perform P2P TE LSPs when performing CAC.
   The use of P2MP TE LSP will now allow for an accounting of the
   unicast and multicast traffic for bandwidth reservation.

   P2MP TE solution solutions MUST support both supports FF and SE reservation style. styles.

   P2MP TE solution MUST be applicable to Diffserv-enabled network networks
   that can provide consistent QoS control in P2MP LSP traffic.

   This

   Any solution SHOULD also satisfy the DS-TE requirement requirements [RFC3564] and
   interoperable
   interoperate smoothly with current P2P DS-TE protocol specification. specifications.

   Note that this requirement document does not make any assumption on
   the type of bandwidth pool used for P2MP TE LSP LSPs which can either be
   shared with P2P TE LSP or be dedicated. dedicated for P2MP use.

5.8 Reoptimization of P2MP TE LSP

   The detection of a more optimal path is an example of a situation
   where P2MP TE LSP re-routing is may be required. While re-routing is in
   progress, an important requirement is avoiding double bandwidth
   reservation (over the common parts between the old and new LSP)
   thorough the use of resource sharing. Make-before-break
   (see [RFC3209]) delivers simultaneously a solution to these
   requirements.

   Make-before-break MUST be supported for a P2MP TE LSP to ensure that
   there is no traffic disruption when the P2MP TE LSP is rerouted.

   There re-routed.

   It is a possibility possibile to achieve make-before-break that only
   applies to a sub-P2MP path tree without impacting the data on the all of
   the other parts of the P2MP path. tree.

   The solution SHOULD allow for make-before-break reoptimization of
   a sub-tree with no impact on the rest of the tree (no label
   reallocation, no change in identifiers...). identifiers, etc.).

   The solution SHOULD also provide the ability for the ingress LSR
   to have a strict control on the reoptimization process.

   Such reoptimization MAY be initiated by the sub-tree root branch
   node. (e.g.
   node (that is, the branch node MAY setup a new sub-tree, then splices splice
   traffic on the new subtree and delete the former sub-tree).

5.9 IPv4/IPv6 support

   A

   Any P2MP TE solution MUST be equally applicable to IPv4/IPv6. IPv4 and IPv6.

5.10 P2MP MPLS Label

   A P2MP TE solution MUST support establishment of both P2P and
   P2MP TE LSP LSPs and MUST NOT impede the operation of P2P TE LSPs within
   the same network. A P2MP TE solution MUST be specified in such
   a way that it allows P2MP and P2P TE LSPs to be signaled on the
   same interface. Labels for P2MP TE LSPs and P2P TE LSPs MAY be
   assigned from shared or dedicated label space(s). Label space
   shareability is implementation specific.

5.11 Routing advertisement of P2MP capability

   This document has identified several

   Several high-level requirements for
   enhancements to routing and signalling protocols have been identified to support determine
   the capabilities of LSRs within a P2MP MPLS. These are needed network. This information is
   to facilitate the computation of P2MP
   paths trees using TE constraints so
   within a network that explicit source-control may be
   applied to the LSP paths as they are signaled through contains LSRs that do not all have the network. same
   capabilities levels with respect to P2MP signaling and data
   forwarding.

   These requirements include capabilities include, but are not restricted limited to:

   - the ability of an LSR to support branching.
   - the ability of an LSR to act as an egress and a branch for the
     same LSP.

   The applicability of these requirements

   It is for further study.
   These expected that it may be appropriate to gather this information
   through extensions to TE IGPs (see [RFC3630] and [IS-IS-TE]), but the
   precise requirements and mechanisms are developed in out of the scope of this
   document. It is expected that a separate document.

5.12 document will cover this
   requirement.

5.12 Multi-Area/AS LSP

   P2MP TE solution solutions SHOULD support multi-Area/AS LSP.

   A separate document may deal with the specifics of inter-area
   and inter-AS multi-area/AS P2MP TE LSPs.

   The precise requirements in support of multi-area/AS P2MP LSPs
   is out of the scope of this document. It is expected that a separate
   document will cover this requirement.

5.13 P2MP MPLS OAM

   Management of P2MP LSPs is as important as the management of P2P
   LSPs.

   The MPLS and GMPLS MIB should modules MUST be enhanced to provide P2MP TE
   LSP management.

   In order to facilitate correct management, P2MP TE LSPs MUST have a
   unique identifier whose definition MAY be
   partially or entirely shared with P2P identifiers.

   OAM facilities will have special demands in P2MP environments
   especially within the context of tracing the paths and connectivity
   of P2MP TE LSP identifiers used LSPs. The precise requirements and mechanisms for
   management purposes. OAM are
   out of the scope of this document. It is expected that a separate
   document will cover these requirements.

5.14 Scalability

   Scalability is a key requirement in P2MP MPLS systems. Solutions
   should
   MUST be designed to scale well with an increase in the number of
   any of the following:
   - the number of recipients, recipients
   - the number of branch points and
   - the number of branches.
   Both scalability of performance and operation must MUST be considered.

   Key considerations may SHOULD include:
   - the amount of refresh processing associated with maintaining a
     P2MP TE LSP.
   - the amount of protocol state that must be maintained by ingress
     and transit LSRs along a P2MP path. tree.
   - the number of protocol messages required to set up or tear down
     a P2MP LSP as a function of the number of egress LSRs.
   - the number of protocol messages required to repair a P2MP LSP
     after failure or perform make-before-break.
   - the amount of protocol information transmitted to manage a P2MP
     TE LSP (i.e. the message size).
   - the amount of potential routing extensions.
   - the amount of control plane processing required by the ingress,
     transit and egress LSRs to add/delete a branch LSP to/from an
     existing P2MP LSP.

5.15 Backwards Compatibility

   It should SHOULD be an aim of any P2MP solution to offer as much backward
   compatibility as possible. An ideal would be to offer P2MP services
   across legacy MPLS networks without any change to any LSR in the
   network.

   If this ideal cannot be achieved, the aim should SHOULD be to use legacy
   nodes as both transit non-branch LSRs and egress LSRs.

   It is a further requirement of all protocol solutions that any LSR
   that implements the solution shall not SHALL NOT be prohibited by that act from
   supporting P2P TE LSPs using existing signaling mechanisms. That is,
   unless administratively prohibited, P2P TE LSPs must MUST be supported
   through a P2MP network.

5.16 GMPLS

   Solutions for MPLS P2MP TE-LSPs when applied to GMPLS P2MP PSC
   or non-PSC TE-LSPs must MUST be backward and forward compatible with
   the other features of GMPLS including:

   o

   - control and data plane separation (IF_ID RSVP_HOP and
     IF_ID ERROR_SPEC),
   o
   - full support of numbered and unnumbered TE links (see [RFC 3477]
     and [GMPLS-ROUTING]),
   o [GMPLS-ROUTE]),
   - use of the GENERALIZED_LABEL_REQUEST and the GENERALIZED_LABEL
     (C-Type 2 and 3) in conjunction with the LABEL_SET and the
     ACCEPTABLE_LABEL_SET object,
   o
   - processing of the ADMIN_STATUS object,
   o
   - processing of the PROTECTION object,
   o
   - support of Explicit Label Control,
   o
   - processing of the Path_State_Removed Flag,
   o
   - handling of Graceful Deletion procedures.

   In addition, since non-PSC TE-LSPs may have to be processed in
   environments where the "P2MP capability" could be limited, specific
   constraints may also apply during the P2MP TE Path computation.
   Being technology specific, these constraints are outside the scope
   of this document. However, technology independent constraints (i.e.
   constraints that are applicable independently of the LSP class)
   should
   SHOULD be allowed during P2MP TE LSP message processing. It has to
   be emphasized that path computation and management techniques shall
   be as close as possible than to those being used for PSC P2P TE LSPs
   and P2MP TE LSPs.

   Finally, note that bi-directional TE LSPs are not applicable to
   multicast traffic. Although many leaf nodes may be considered as
   senders in a multicast group, a P2MP TE LSP models a single
   distribution tree from a sender to multiple recipients. If such
   a tree were made bi-directional it would be a multipoint-to-point
   tree in the reverse direction.

5.17 Requirements for Hierarchical P2MP TE LSPs

   [LSP-HIER] define defines concepts and procedures for P2P LSP hierarchy. They
   should

   These procedures SHOULD be extended to support P2MP LSP hierarchy.

   The P2MP MPLS-TE solution SHOULD support the concept of region and
   region hierarchy (PSC1<PSC2<PSC3<PSC4<L2SC<TDM<LSC<FSC).

   Particularly it SHOULD allow a Region i P2MP TE LSP to be nested
   into a region j P2MP TE LSP or multiple region j P2P TE LSPs,
   providing that i<j.

   The precise requirements and mechanisms for this function are out of
   the scope of this document. It is expected that a separate document
   will cover these requirements.

5.18 P2MP Crankback routing

   P2MP solution solutions SHOULD support cranckback requirements as defined in
   [CRANKBACK]. In particular, it they SHOULD provide sufficient
   information to a branch LSR from downstream LSRs to allow the branch
   LSR to re-route a sub-tree around any failures or problems in the
   network.

6. Security Considerations

   This requirements draft document does not define any protocol extensions
   and does not, therefore, make any changes to any security models.

   It should be noted that P2MP signaling mechanisms built on P2P
   RSVP-TE signaling are likely to inherit all of the security
   techniques and problems associated with RSVP-TE. These problems may
   be exacerbated in P2MP situations where security relationships may
   need to maintained between an ingress and multiple egresses. Such
   issues are similar to security issues for IP multicast.

   It is a requirement that documents offering solutions for P2MP LSPs
   MUST have detailed security sections.

7. Acknowledgements

   The authors would like to thank George Swallow, Ichiro Inoue and
   Dean Cheng for their review and suggestions on an earlier draft of
   this document.

8. References

8.1 Normative References

   [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan,
   V. and G. Swallow, "RSVP-TE: Extensions to RSVP

   [RFC2119]     Bradner, S., "Key words for LSP Tunnels",
   RFC 3209, December 2001.

   [RFC3031] Rosen, E., Viswanathan, A. and R. Callon, "Multiprotocol
   Label Switching Architecture", use in RFCs to Indicate
                 Requirement Levels", BCP 14, RFC 3031, January 2001. 2119, March 1997.

   [RFC2475]     Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.
                 and W. Weiss,  "An Architecture for Differentiated
                 Services", RFC 2475, December 1998.

   [RFC2597]     Heinanen, J., Baker, F., Weiss, W. and J. Wroclawski,
                 "Assured Forwarding PHB Group", RFC 2597, June 1999.

   [RFC3246] Davie, B., Charny, A., Bennet, J.C.R., Benson, K., Le
   Boudec, J.Y., Davari, S., Courtney, W., Firioiu, V. and D. Stiliadis,
   "An Expedited Forwarding PHB (Per-Hop Behavior)", RFC 3246,
   March 2002.

   [RFC2362] D. Estrin, D. Farinacci, A. Helmy, D. Thaler, S. Deering,
   M. Handley, V. Jacobson, C. Liu, P. Sharma, L. Wei, "Protocol
   Independent Multicast-Sparse Mode (PIM-SM): Protocol Specification.",
   RFC 2362, June 1998.

   [RFC2702]

   [RFC2702]     D. Awduche, J. Malcolm, J. Agogbua, M. O'Dell, J.
                 McManus, "Requirements for Traffic Engineering Over
                 MPLS", RFC2702, September 1999.

   [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.

   [RFC3246]     Davie, B., Charny, A., Bennet, J.C.R., Benson, K., Le
                 Boudec, J.Y., Davari, S., Courtney, W., Firioiu, V. and
                 D. Stiliadis, "An Expedited Forwarding PHB (Per-Hop
                 Behavior)", RFC 3246, March 2002.

   [RFC3667]     Bradner, S., "IETF Rights in Contributions", BCP 78,
                 RFC 3667, February 2004.

   [RFC3668]     Bradner, S., Ed., "Intellectual Property Rights in IETF
                 Technology", BCP 79, RFC 3668, February 2004.

8.2 Informational References

   [PIM-SM] B. Fenner, M. Hadley, H. Holbrook, I. Kouvelas, "Protocol
   Independent Multicast - Sparse Mode (PIM-SM):Protocol Specification
   (Revised)", draft-ietf-pim-sm-v2-new-08.txt, October 2003.

   [BGP/MPLS IP VPNs] E. Rosen, Y.Rekhter, Editor, "BGP/MPLS IP VPNs",
   draft-ietf-l3vpn-rfc2547bis-01.txt, September 2003.

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

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

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

   [GMPLS-ROUTING]

   [RFC3564]     F. Le Faucheur, W. Lai, "Requirements for Support of
                 Differentiated Services-aware MPLS Traffic
                 Engineering", RFC 3564, July 2003.

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

   [PIM-SM]      B. Fenner, M. Hadley, H. Holbrook, I. Kouvelas,
                 "Protocol Independent Multicast - Sparse Mode (PIM-SM):
                 Protocol Specification (Revised)", draft-ietf-pim-sm-
                 v2-new-08.txt, October 2003.

   [BGPMPLS-VPN] E. Rosen, Y.Rekhter, Editor, "BGP/MPLS IP VPNs",
                 draft-ietf-l3vpn-rfc2547bis-01.txt, September 2003.

   [GMPLS-ROUTE] K. Kompella, Y. Rekhter,  Editor, "Routing Extensions
                 in Support of Generalized Multi-Protocol Label
                 Switching", draft-ietf-ccamp-gmpls-routing-08.txt,
                 October 2003.

   [STEINER]     H. Salama, et al., "Evaluation of Multicast Routing
                 Algorithm for Real-Time Communication on High-Speed
                 Networks," IEEE Journal on Selected Area in
                 Communications, pp.332-345, 1997.

   [DJIKSTRA] E. W. Djikstra, "A note on two problem in connection with
   graphs," Numerische Mathematik, vol.1, pp.269-271, 1959.

   [IPMCAST-MPLS] D. Ooms, B. Sales, W. Livens, A. Acharya, F. Griffoul
   and F. Ansari, "Overview of IP Multicast in a Multi-Protocol Label
   Switching (MPLS) Environment", RFC3353, August 2002.

   [FRR]         P. Pan, D. Gan, G. Swallow, J. P. Vasseur, D. Cooper,
                 A. Atlas, M. Jork,"Fast Reroute Extensions to RSVP-TE
                 for LSP Tunnels", draft-ietf-mpls-rsvp-lsp-fastreroute-03.txt, July 2003.

   [RFC3564] F. Le Faucheur, W. Lai, "Requirements for Support of
   Differentiated Services-aware MPLS Traffic Engineering", RFC3564, draft-ietf-mpls-rsvp-lsp-fastreroute-
                 03.txt, July 2003.

   [OSPF-TE] D. Katz, D. Yeung, K. Kompella, "Traffic Engineering
   Extensions to OSPF Version 2", draft-katz-yeung-ospf-traffic-08.txt,
   September 2002.

   [IS-IS-TE]    Henk Smit, Tony Li, "IS-IS extensions for Traffic
                 Engineering", draft-ietf-isis-traffic-04.txt, December
                 2002.

   [CRANKBACK]   A. Farrel, A. Satyanarayana, A. Iwata, N. Fujita, G. Ash
                 Ash, S. Marshall, "Crankback Signaling Extensions for
                 MPLS Signaling",
   draft-ietf-ccamp-crankback-00.txt, December 2003. draft-ietf-ccamp-crankback-01.txt,
                 January 2004.

   [LSP-HIER]    K. Kompella, Y. Rekhter, "LSP Hierarchy with
                 Generalized MPLS TE", draft-ietf-mpls-lsp-hierarchy-08.txt, draft-ietf-mpls-lsp-hierarchy-
                 08.txt, September 2002.

   [NODE-ID]     Vasseur, Ali and Sivabalan, "Definition of an RRO node-id node-
                 id subobject", draft-ietf-mpls-nodeid-subobject-01.txt,
                 June 2003.

9. Author's Addresses Editor's Address

   Seisho Yasukawa
   NTT Network Service Systems Laboratories, NTT Corporation
   9-11, Midori-Cho 3-Chome
   Musashino-Shi, Tokyo 180-8585 180-8585,
   Japan
   Phone: +81 422 59 4769
   Email: yasukawa.seisho@lab.ntt.co.jp

10. Authors' Addresses

   Dimitri Papadimitriou (Alcatel)
   Alcatel
   Francis Wellensplein 1,
   B-2018 Antwerpen,
   Belgium
   Phone : +32 3 240 8491
   Email: dimitri.papadimitriou@alcatel.be

   JP Vasseur
   Cisco Systems, Inc.
   300 Beaver Brook Road
   Boxborough, MA 01719 01719,
   USA
   Email: jpv@cisco.com

   Yuji Kamite
   NTT Communications Corporation
   Tokyo Opera City Tower
   3-20-2 Nishi Shinjuku, Shinjuku-ku,
   Tokyo 163-1421,
   Japan
   Email: y.kamite@ntt.com

   Rahul Aggarwal
   Juniper Networks
   1194 North Mathilda Ave.
   Sunnyvale, CA 94089
   Email: rahul@juniper.net
   Alan Kullberg
   Motorola Computer Group
   120 Turnpike Rd.
   Southborough, MA 01772
   Email: alan.kullberg@motorola.com

   Adrian Farrel
   Old Dog Consulting
   Phone: +44 (0) 1978 860944
   Email: adrian@olddog.co.uk

   Markus Jork
   Avici Systems
   101 Billerica Avenue
   N. Billerica, MA 01862
   Phone: +1 978 964 2142
   Email: mjork@avici.com

   Andrew G. Malis
   Tellabs
   2730 Orchard Parkway
   San Jose, CA 95134
   Phone: +1 408 383 7223
   Email: andy.malis@tellabs.com

   Jean-Louis Le Roux
   France Telecom
   2, avenue Pierre-Marzin
   22307 Lannion Cedex
   France
   Email: jeanlouis.leroux@francetelecom.com

10.

11. Intellectual Property Consideration

   The IETF takes no position regarding the validity or scope of any intellectual property
   Intellectual Property Rights or other rights that might be claimed
   to pertain to the implementation or use of the technology
   described in this document or the extent to which any license
   under such rights might or might not be available; neither nor does it
   represent that it has made any independent effort to identify any
   such rights.  Information on the
   IETF's procedures with respect to rights
   in standards-track
   and standards-related documentation RFC documents can be found in BCP-11. BCP 78 and BCP 79.

   Copies of claims of rights IPR disclosures made available for publication to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use
   of such proprietary rights by
   implementors implementers or users of this
   specification can be obtained from the IETF Secretariat. on-line IPR repository
   at http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention
   any copyrights, patents or patent applications, or other
   proprietary rights which that may cover technology that may be required
   to practice implement this standard.  Please address the information to the
   IETF Executive Director.

11. at ietf-ipr@ietf.org.

11.1 IPR Disclosure Acknowledgement

   By submitting this Internet-Draft, I certify that any applicable
   patent or other IPR claims of which I am aware have been disclosed,
   and any of which I become aware will be disclosed, in accordance with
   RFC 3668.

 12. Full Copyright Statement

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   for the purpose of developing Internet standards in which
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