Network Working Group                              Seisho Yasukawa (NTT)
Internet Draft                           Dimitri Papadimitriou (Alcatel)
                                           Jean Philippe Vasseur (Cisco)
Adrian Farrel (Old Dog)                 Yuji Kamite (NTT Communications)
Markus Jork (Avici)                             Rahul Aggarwal (Juniper)
Andrew G. Malis(Tellabs)                        Alan Kullberg (Motorola)                                                    Editor

Expiration Date: March June 2004                                  January 2004                                 October 2003

       Requirements for Point to Multipoint extension to RSVP-TE
                <draft-ietf-mpls-p2mp-requirement-00.txt>
               <draft-ietf-mpls-p2mp-requirement-01.txt>

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

Abstract

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

1. Introduction

   Existing MPLS Traffic Engineering (MPLS-TE) allows for strict QoS
   guarantees, resources optimization, and fast failure 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 of 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
   infrastructure. TE.

   It is intended that potential solutions, that specify RSVP-TE
   procedures for P2MP TE LSP setup, use these requirements as a
   guideline. 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 solution would be 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 environemnt, large-scale environment, P2MP TE mechanisms are required. required
   specifically to support P2MP TE LSPs. Existing MPLS P2P TE mechanisms have to be enhanced to
   [RFC3209] do not support P2MP TE LSP setup. LSPs so new mechanisms must be
   developed.

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

   A P2MP TE LSP will be setup set up with TE constraints and will allow
   efficient 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 receivers to/from an
   existing P2MP TE LSP.

   Moreover, multicast traffic cannot currently benefit from P2P TE LSP.
   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 by means of CAC.

   The problem statement is discussed in the following section. This
   document discusses various applications that can use P2MP MPLS TE. 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 (referred (also referred to as the leaf).

   P2MP path:

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

      This path may be viewed as a tree.

   sub-P2MP path:

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

   P2P sub-LSP path:

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

   ingress LSR:

      It

      The LSR that is responsible for initiating the signaling messages
      that set
      up, modify and teardown up the LSP

   branch LSR:

      A 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. A branch LSR receives
      a single MPLS frame, makes a duplicate of it, and sends each to
      downstream interfaces.

   graft LSR:

      A

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

   prune LSR:

      A

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

   egress LSR:

      One of potentially many destinations of the P2MP LSP. Note
      that in some P2MP paths, an egress LSR may also have one or more
      downstream LSRs. Such an egress LSR may also be referred to
      as a branch LSR.

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].

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 is may not be
   sufficient for P2MP applications for many of the same reasons that
   it is not sufficient for unicast applications TE and constraint based applications. Note also that
   multicast tree provided by existing IP multicast routing protocols
   are required not optimal, which may lead to enable significant bandwidth wasting.
   TE and scale the efficient management of network
   resources, mechanism to prevent congestion (including Constraint Based Routing, including Call Admission
   Function combined with Control
   (CAC), explicit source routing, Diffserv), routing and bandwidth reservation, is required
   to enable sub-second rerouting 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 setup. LSP.

3.2. Requirements Overview

   This document is proposing 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 setup 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 receivers 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 (so - the so called "Make before
   break" procedure).

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

   The MPLS WG will specify how to build solutions for the setup a P2MP TE LSP. LSPs. The usage of
   those solutions will be application dependent and is out of the scope
   of this draft. However, it is a requirement that those solutions be
   applicable to GMPLS as well as 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. 1

   The above figure above shows I(Ingress)-LSR1, E(Egress)-LSR2, E-LSR3 a single ingress (I-LSR1), and
   E-LSR4. 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. E-LSR2, E-LSR3
   Receivers:R1, R2, R3 and E-LSR4 R4 are attached to receivers that are interested in receiving traffic for
   the application. E-LSR2, E-LSR3 and
   E-LSR4.

   The following are the objectives that we wish to achieve:

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

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

         Typical constraints are bandwidth requirements, resource class
         affinities, fast rerouting, preemption, along with several
         potential other constraints. preemption. There should not be any
         restriction on the possibility to support the set of
         constraints already defined for point to point TE LSPs.

      b) Set up a 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 information which could have been computed by
         some off-line or on-line algorithms. information.

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

      d) The P2MP TE LSP should be setup by enhancing existing RSVP-TE
         P2P procedures and without any requirement for multicast
         routing protocol in the network core.
      e) The solution should provide the ability to gracefully modify
         P2MP TE LSP (i.e add/remove some part of the p2mp TE LSP
         without requiring to entirely tearing down or setting up If a
         completely new p2mp TE LSP). Such operations should be
         performed receiver (R5) expresses an interest in receiving
         traffic, a non traffic disruptive fashion. In this case, new path is determined and a sub-P2MP path LSR2->E-LSR5 from
         LSR2 to E-LSR5 is grafted and pruned based on
         traffic destination change. onto the P2MP path. 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,
   if any. 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 and not limited to the described applications.

4.1 P2MP tunnel TE LSP for IP multicast data

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

   Note that a P2MP TE LSP can be established over multiple AREAs/ASs. 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

   In this scenario,

   P2MP TE LSPs are utilized to construct applicable in a P2MP backbone network for to construct or
   support a multicast network (e.g. network(e.g. IPmcast network). Each
   The IP multicast access networks is are interconnected by a P2MP TE LSP. LSPs.
   A P2MP TE LSP is established from an ingress LSR which accomodates accommodates
   an IP multicast network that has a Mcast Source multicast source to multiple
   egress LSRs which accomodate 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 each
   the ingress/egress LSR exchanges LSRs exchange IP multicast routing messages as
   neighbour router. 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
   each 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 at a rapid rate. 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 and
   to allow the ingress LSR to hold sufficient information in order to
   optimise multicast FEC on sender nodes. 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 BA 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.

4.4 VPN multicast network

   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 VPN VPNs like BGP/MPLS based IP VPN VPNs
   [BGP/MPLS IP VPNs], 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's 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). In

   An Ethernet multipoint L2 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 the
   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, 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 Network Networks

   GMPLS supports only P2P TE-LSPs just like MPLS. GMPLS enhances MPLS
   to support four new classes of interfaces 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.

   This also means that solutions

5. Detailed requirements for MPLS P2MP TE-LSPs when applied
   to GMPLS TE extensions

5.1 P2MP PSC and non-PSC TE-LSPs shall LSP tunnels

   The P2MP RSVP-TE extensions 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 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 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 those being used for PSC P2P and P2MP TE
   LSPs.

5. Requirements for P2MP capability extension

5.1 P2MP LSP tunnels

   The P2MP RSVP-TE extensions MUST be applicable to signaling LSPs applicable to signaling LSPs
   of different traffic types. For example, it 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], technology [RFC3031], traffic is classified with
   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.

   In order to scale to a large number of branches, P2MP TE LSPs should
   be identified by unique identifier 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 formation need to be applied to
   meet various needs such as QoS requirements and operational constraints.
   Some P2MP applications may request a bandwidth guarantees, guaranteed P2MP path
   which satisfies end-to-end delay requirements,
   and minimization of the total requirements. And some operators
   may want to set up a cost minimum P2MP path cost. by specifying branch LSRs
   explicitly.

   The P2MP TE solution therefore MUST provide a means of establishing
   arbitrary P2MP paths. paths under the control of an external path
   computation process or path configuration process or dynamic path
   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                        SPF P2MP path

                Figure 4 Examples of P2MP TE LSP topology

   One example is Steiner[STEINER] P2MP path (Cost minimum P2MP path).
   This P2MP path is suitable for constructing cost minimum P2MP path.
   To realize this P2MP path, several intermediate LSRs must be both
   MPLS data terminating LSR and transit LSR (LSR E, F, G, H, I, J, K,
   in the figure). figure 4). This means that the LSR 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
   terminate
   bud LSR between a an ingress LSR and egress LSRs.

   Another example is CSPF (Constraint Shortest Path Fast) P2MP path. 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. This P2MP path is suitable for carrying real time
   traffic.

   To support explicit setup of any reasonable P2MP path shape, a P2MP
   TE solution must MUST support some form of explicit source-based control
   of the P2MP path. This path which can be used by 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
   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 or as a whole. branches.

   Here also, 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 is completely specified if all of the required
   branches and hops between a sender and leaf LSR are indicated.

   A P2MP path 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 or AS numbers.
   A partially specified P2MP path 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 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 to resolve a partially specified path
   into a (more) completely specified path.

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

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

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

5.4 P2MP TE LSP establishment, teardown, and modification mechanisms

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

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

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

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 be reported upstream
   as for a P2P LSP.

   Protection and

   The solution SHOULD provide recovery techniques SHOULD be applied such as protection
   and restoration allowing to the recover any impacted sub-P2MP TE LSPs.
   In particular, it is required to provide fast protection mechanisms
   applicable to P2MP TE LSP similar to
   build new sub-P2MP 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 use backup sub-P2MP not be shared with P2P TE
   LSPs backup paths.

   A P2MP TE solution MUST support P2MP fast protection mechanism
   to restore the
   data handle P2MP applications sensitive to the severed egress nodes. 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 it
   should be a matter of local policy at the ingress whether the P2MP
   LSP is retained.

   When all egress node downstreams of a branch node have become
   disconnected from the P2MP path, 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.
   Since the faults that severed the various downstream egress nodes
   from the P2MP path may be disperate, 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 particular egress node, around
   the failure point.

   Solutions MAY include the facility for transit LSRs and particularly
   branch nodes to recompute sub-P2MP paths to restore them after
   failures. In the event of successful repair, no error notification is
   reported to upstream nodes, but the new paths are reported if route
   recording is in use. Crankback requirements are discussed in
   [CRANKBACK].

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, operation of some
   local recovery mechanism like Fast Reroute [FRR]. A network operator
   uses this information to manage P2MP TE LSP. Therefore, topology
   information MUST be collected and updated after P2MP TE LSP
   establishment and modification process.

   For this purpose, 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 topology
   information after P2MP LSP establishment and modification process.

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

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

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

   P2MP TE LSP share network resource with P2P TE LSP. Therefore it is
   important to use CAC and QoS as P2P TE LSP for easy and scalable
   operation.

   In particular, it should be highlighted that because
   mutliacst
   Multicast traffic cannot make use of point to point TE LSP, multicast
   traffic cannot be easily taken into account by point to point in
   order to perform 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 MUST both supports FF and SE reservation style.

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

   This solution SHOULD also satisfy DS-TE requirement [RFC3564] and
   interoprable
   interoperable smoothly with current P2P DS-TE protocol specification.

5.8 Rerouting of

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

5.8 Reoptimization of P2MP TE LSP

   The detection of a more optical optimal path and network resource failure(s)
   (such as link(s) and node(s)) are examples is an example of situation where
   P2MP TE LSP re-routing is needed. may be required. While re-routing is in
   progress, an important requirement is avoiding traffic disruption. An additional
   requirement is avoiding double bandwidth
   reservation (over the common parts between the old and new LSP) through
   thorough the use of resource sharing. Make-before-break
   (see [RFC 3209]) [RFC3209]) delivers simultaneously a solution to these
   requirements.

   Make-Before-Break

   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.

   And

   There is a P2MP TE solution MUST support P2MP fast rerouting mechanism possibility to handle P2MP applications sensitive achieve make-before-break that only
   applies to a sub-P2MP path without impacting the data on the all of
   the other parts of the P2MP path.

   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...).

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

5.9 IPv4/IPv6 support

   A P2MP TE solution MUST be applicable to IPv4/IPv6.

5.10 P2MP MPLS Label

   A P2MP TE solution MUST support establishment of both P2P and
   P2MP TE LSP 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 high-level requirements for
   enhancements to routing and signalling protocols to support
   P2MP MPLS. These are needed to facilitate the computation of P2MP
   paths using TE constraints so that explicit source-control may be
   applied to the LSP paths as they are signaled through the network.

   These requirements include but not restricted to:

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

   The applicability of these requirements is for further study.
   These requirements are developed in a separate document.

5.12 Multi-Area/AS LSP

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

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

5.13 P2MP MPLS management

   The MPLS MIB should be enhanced to provide P2MP TE LSP management.
   P2MP TE LSPs MUST have a unique identifier whose definition MAY be
   partially or entirely shared with P2P TE LSP identifiers used for
   management purposes.

6. Security Considerations

   Security considerations will

5.14 Scalability

   Scalability is a key requirement in P2MP MPLS systems. Solutions
   should be addressed designed to scale well with an increase in a future revision the number of
   this document.

7. Acknowledgements

   The authors would like to thank George Swallow, Ichiro Inoue and
   Dean Cheng for his review
   any of the following: the number of recipients, the number of branch
   points and suggestion the number of an earlier draft branches. Both scalability of this
   document.

8. References

   [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan,
   V. performance
   and G. Swallow, "RSVP-TE: Extensions operation must be considered.

   Key considerations may include:
   - the amount of refresh processing associated with maintaining a
     P2MP TE LSP.
   - the amount of protocol state that must be maintained by transit
     LSRs along a P2MP path.
   - the number of protocol messages required to RSVP for LSP Tunnels",
   RFC 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 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 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 be prohibited by that act from
   supporting P2P TE LSPs using existing signaling mechanisms. That is,
   unless administratively prohibited, P2P TE LSPs 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 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 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 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 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 concepts and procedures for P2P LSP hierarchy. They
   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.

5.18 P2MP Crankback routing

   P2MP solution SHOULD support cranckback requirements as defined in
   [CRANKBACK]. In particular, it 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 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
   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
   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 for LSP Tunnels",
   RFC 3209, December 2001.

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

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

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 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]  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 1997.

   [DJIKSTRA] E. W. Djikstra, "A note on two problem in connection with
   graphs," Numerische Mathematik, vol.1, pp.269-271, 1959 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 2003.

   [RFC3564] F. Le Faucheur, W. Lai, "Requirements for Support of
   Differentiated Services-aware MPLS Traffic Engineering", RFC3564,
   July 2003 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 2002.

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

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

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

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

9. Author's Addresses

   Seisho Yasukawa
   NTT Network Service Systems Laboratories, NTT Corporation
   9-11, Midori-Cho 3-Chome
   Musashino-Shi, Tokyo 180-8585 Japan
   Phone: +81 422 59 4769
   EMail:
   Email: yasukawa.seisho@lab.ntt.co.jp
   Dimitri Papadimitriou (Alcatel)
   Francis Wellensplein 1,
   B-2018 Antwerpen, Belgium
   Phone : +32 3 240 8491
   EMail:
   Email: dimitri.papadimitriou@alcatel.be

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

   Yuji Kamite
   NTT Communications Corporation
   Innovative IP Architecture Center,
   Tokyo Opera City Tower 21F,
   20-2, 3-chome, Nishi-Shinjuku,
   3-20-2 Nishi Shinjuku, Shinjuku-ku,
   Tokyo, Tokyo
   163-1421, Japan.
   EMail: 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:
   Email: adrian@olddog.co.uk

   Markus Jork
   Avici Systems
   101 Billerica Avenue
   N. Billerica, MA 01862
   email: mjork@avici.com
   phone:
   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. Intellectual Property Consideration

   The IETF takes no position regarding the validity or scope
   of any intellectual property 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 does it represent that it has made any
   effort to identify any such rights.  Information on the
   IETF's procedures with respect to rights in standards-track
   and standards-related documentation can be found in BCP-11.
   Copies of claims of rights made available for publication
   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 or users of this specification can be obtained
   from the IETF Secretariat.

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

11. Full Copyright Statement

   Copyright (C) The Internet Society (2004). All Rights
   Reserved.

   This document and translations of it may be copied and
   furnished to others, and derivative works that comment on
   or otherwise explain it or assist in its implementation may
   be prepared, copied, published and distributed, in whole or
   in part, without restriction of any kind, provided that the
   above copyright notice and this paragraph are included on
   all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by
   removing the copyright notice or references to the Internet
   Society or other Internet organizations, except as needed
   for the purpose of developing Internet standards in which
   case the procedures for copyrights defined in the Internet
   Standards process must be followed, or as required to
   translate it into languages other than English.

   The limited permissions granted above are perpetual and
   will not be revoked by the Internet Society or its
   successors or assigns. This document and the information
   contained herein is provided on an "AS IS" basis and THE
   INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE
   DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT
   NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
   PURPOSE.