One document matched: draft-yasukawa-mpls-p2mp-requirement-00.txt







MPLS Working Group                               Seisho Yasukawa (NTT)
Internet Draft                                   Ichiro Inoue    (NTT)

Expiration Date: August 2003
                                                          Februarly 2003



   Requirements for Point-to-Multipoint capability extension to MPLS
             <draft-yasukawa-mpls-p2mp-requirement-00.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
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Abstract

   This document presents a set of requirements for Point-to-Multipoint
   (P2MP) capability extension to Multiprotocol Label Switching (MPLS).
   It identifies the functional and performance extensions required to
   realize Content Distribution Network (CDN) by MPLS technology.
   It also identifies functional extensions required to implement
   CDN/VoIP/VPN sevice convergence network. These extensions can be used
   to provide high performance and scalable broadband service network
   with MPLS technology.





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   Table of Contents

   1. Introduction ..................................................  3
   2. Terminology and conventions ...................................  3
      2.1 Terminology ...............................................  3
      2.2 Conventions ...............................................  5
   3. Typical Network attribute and architecture of
      Content Distribution Service...................................  5
      3.1 Service type and its characteristics ......................  5
      3.2 Live video distribution service ...........................  5
      3.3 Video Broadcasting service ................................  7
      3.4 Video on Demand service ...................................  9
      3.5 Content Distribution Network architecture ................. 11
   4. Requirements for P2MP capability exptension ................... 11
      4.1 P2MP LSP tunnels .......................................... 11
      4.2 P2MP LSP topoplogy and Tree explicit routing .............. 11
      4.3 Calculation of P2MP Path .................................. 12
      4.4 P2MP LSP establishment, teardown, and modification
          mechanisms ................................................ 13
      4.5 Management of P2MP LSP tunnels ............................ 13
      4.6 QoS control of P2MP LSP tunnels ........................... 14
      4.7 P2MP TE ................................................... 14
      4.8 IPv4/IPv6 support ......................................... 15
      4.9 P2P and P2MP LSP establishment ............................ 15
      4.10 Interworking function with IP multicast .................. 15
   5. Requirements for Service convergence network .................. 15
      5.1 CDN/VoIP/VPN service convergence network .................. 15
      5.2 VPN Multicast ............................................. 15
   6. Security Considerations........................................ 15
   7. Acknowledgements .............................................. 16
   8. References .................................................... 16
   9. Author's Addresses ............................................ 17



















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1. Introduction

   With rapid dissemination of broadband IP access services, like xDSL
   and FTTH, many service providers seek a chance for deploying new
   broadband IP services networks for their customers. Among multiple
   candidates, Content Distribution (CD), Voice over IP (VoIP) and
   Virtual Private Network (VPN) services are the most attractive
   broadband services to service provider and their customers.

   To differentiate these services from conventional best effort
   Internet access service, Quality of Service (QoS) control, Traffic
   Engineering (TE) and Reliability control mechanisms are required to
   broadband IP service network. Because MPLS already has all of these
   mechanisms in its protocol architecture, it is assumed that
   developing broadband IP service network by MPLS technology is most
   the promising way.

   But many of these services, such as video broadcasting, video
   conference and VPN multicast service require not only P2P
   transmission capability but also P2MP transmission capability
   with much stricter QoS control, more sophisticated TE and more stable
   reliability control requirement. Therefore, P2MP capability extension
   is required to conventional MPLS.

   This manuscript presents a set of requirements for P2MP capability
   extensions to MPLS. It identifies the functional and performance
   extensions required to realize Content Distribution Network (CDN)
   by MPLS technology. It also identifies functional extensions required
   to implement broadband service convergence network.


2. Terminology and conventions

2.1 Terminology

   The reader is assumed to be familiar with the terminology in [1],
   [2], [3] and [4].

   P2P:

      Point-to-point

   P2MP:

      Point-to-multipoint

   P2MP LSP:




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      A label switched path that has one unique ingress lsr (also
      referred to as the root) and more than one egress label switching
      router.

   sender node:

      Headend of the P2MP LSP. It controls the P2MP LSP layout
      and places traffic onto it by pushing a label.

   Branch LSR:

      A label switching router (LSR) that has more than one downstream
      LSR. A branch LSR receives a single MPLS frame, makes a duplicate
      of it, and sends each to downstream interfaces.

   join leaf node:

      A leaf node trying to join a P2MP LSP.

   leave leaf node:

      A leaf node trying to leave a P2MP LSP that it has joined

   graft node:

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

   prune node:

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

   Subtree:

      A subtree is a portion of a P2MP tree starting at a particular LSR
      that is a member of the P2MP tree and includes ALL downstream
      nodes that are also members of the P2MP tree.

   EPG:

      Electric Program Guide.

   NWA:

      Network Agent is an agent which authenticates client's IGMP
      message and performs call admission control considering network
      resource.



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   RTSP:
      Real Time Streaming Protocol.

2.2 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. Typical Network attribute and architecture of Content Distribution
   Service

3.1 Service type

   Major candidates for CDS are Live video distribution, video
   broadcasting and video-on-demand service.

   Typical bandwidth of these streaming service ranges from 500kbps to
   6Mbps because they are encoded and transmitted by MPEG4 and
   MPEG6 compression technology.

   These streaming services have the following characteristics. Each
   streaming service require much higher bandwidth, and has longer
   session-on-time compared with conventional IP session. And these
   service are very sensitive to packet loss.

   Therefore, these streaming services require tight QoS control.

3.2 Live video distribution service

   Live video distribution service is one of the streaming service
   which distribute live streaming video data to multiple users on
   demand basis. Live video distribution from baseball park or concert
   hall and e-learning are examples of this service.

   In this service, a streaming server can attach and transmit live
   video streaming data to any of the provider edge nodes in this
   netwok. And any of customer can Join and Leave this streaming service
   by its session control signaling after authentication. Depending on
   the locations of the streaming receivers, a single P2MP lsp is
   established dynamically between a sender edge node and receiver
   edge nodes. It is desirable that this single P2MP lsp convey single
   IP multicast traffic that is transmitted by this streaming source.
   And it is desirable that network resource are reserved dynamically
   depending on reciever's viewing status. This means that unnecessary
   leaf LSP that composed of P2MP LSP must be torn down dynamically
   when all of the receivers that belong to this leaf edge node leave



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   from this service. And vice versa, necessary leaf LSP must be
   established dynamically between branch LSR and leaf edge nodes when
   a receiver newely join in this service. The P2MP LSP is totally torn
   down when streaming source finish transmitting the data or all of
   reciever leave from this service.

   Considering the situation that live video streaming service request
   real time transmission with small delay variation and dynamics of
   P2MP LSP topology, it is desirable to use Shortest Path Fast (SPF)
   algorithm [DJIKSTRA] when calculating P2MP LSP topology.

   Tree size of P2MP LSP varies greatly according to application type of
   Live streaming service. It is assumed that leaf size changes from a
   small number of nodes to a thousand nodes according to the
   application. But bandwidth of live streaming is small and its
   influence is not big. Therefore it is better to setup a P2MP LSP with
   delay optimized topology even if the P2MP LSP has big leaf size.

   Following figure shows one of the example of joining sequence for
   Live streaming video service. In this example, a client request
   Content Platform (CPF) of EPG. After passing authentication, client
   receive EPG from CPF. Selecting live video streaming channel, client
   request CPF of encryption decoder key. Recieving an encryption key,
   client request leaf node of a multicast streaming data by IGMP with
   authentication key[IGAP]. This message is transffered to NWA for
   authentication. After authentication performed by NWA, NWA setup a
   leaf LSP between Graft node and Leaf node and enable IGMP Join
   operation on leaf node. In this way, P2MP LSP is dynamically set and
   live video streaming data is transmitted to the client.






















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                  +-----+   +-----+
                  | CPF |<=>| NWA |
                  +-----+   +-----+
                     /     /  \   \
                    /     /    \   +--------------+
                   /     /      \                  \
  +------+     +--------+       +--------+       +--------+     +------+
  |client|-----| Leaf N |-------|Graft N |-------|Sender N|-----|server|
  +------+     +--------+       +--------+       +--------+     +------+

     |             | |         |    |                 |             |
     |---EPG Req---|>|         |    |                 |             |
     |<--EPG Rep---|-|         |    |                 |             |
     |---Key Req---|>|         |    |                 |             |
     |<--Key Rep---|-|         |    |                 |             |
     |             | |         |    |<=== Live video stream ========|
     |--- IGMP --->| |         |    |                 |             |
     |             |-|--Auth-->|    |                 |             |
     |             |<|---Auth--|    |                 |             |
     |<-- IGMP ----| |         |----|-Graft request ->|             |
     |             |<|-- Path -|----|<---- Path ------|             |
     |             |-|-- Resv -|--->|----- Resv ----->|             |
     |<============|=|======== |====|==== Live video stream ========|
     |             | |         |    |                 |             |

            Figure 1 Live video streaming service sequence


   Several schemes exist to setup a P2P leaf LSP in addition to a scheme
   disribed above. Implementing scheme is decided based on network
   management policy.

3.3 Video Broadcasting Service

   Video Broadcasting Service is one of the streaming service which
   distribute streaming video data to multiple users on static basis.
   IP/TV is one of this service.

   In this service, a broadcast streaming server is placed at central
   data center and it transmits streaming contents by IP multicast
   technology. A static P2MP LSP is established between a sender edge
   node and all of the leaf nodes which accomodate broadcast receivers.
   It is desirable that single P2MP LSP convey multiple IP multicast
   streaming traffic. Therefore, all of broadcast streaming data are
   transmitted to leaf edge node in static manner.

   In this service model, a receiver can enjoy watching video stream by
   selecting necessary video channel from multiple channel.



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   This P2MP LSP can be utlized as backbone technology for both IP/TV
   application and CATV application.

   If a service provider want to provide 50 broadcast streaming channel
   by MPEG2 technology which has 6Mbps transmission bandwith. The P2MP
   LSP must handle 300Mbps broadcast video streaming traffic in a single
   P2MP LSP.

   Considering the influence of this big bandwith and the situation that
   these video stream are transmitted to every leaf edge node in static
   manner, it is desirable to use Steiner tree calculation algorithm
   [STEINER] that can minimize the necessary transmission bandwidth of
   this P2MP tree.

   Tree size of P2MP LSP varies greatly according to application type
   of video broadcasting service. But it is easily assumed that leaf
   size becomes up to a thousand when realizing a nation wide broadcast
   service.

   To enable scalable operation, a mechanism that can change bandwidth
   of established P2MP LSP freely witout disrupting transmission is
   useful. It is also useful to provide partial P2MP tree modification
   mechanism because it enables scalable network design and operation.

   Following figure shows one of the example of service sequence for
   video broadcasting service. In this example, a client request CPF of
   EPG. After passing authentication, client receive EPG from CPF.
   Selecting video broadcast channel, client request CPF of encryption
   decoder key. Recieving encryption key, client request leaf node of a
   multicast streaming data by IGMP with authentication key[IGAP]. This
   message is transffered to NWA for authentication. After
   authentication performed at NWA, NWA enables IGMP Join operation on
   leaf node. After this process, requested video streaming data is
   transmitted to the client.

















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                  +-----+   +-----+
                  | CPF |<=>| NWA |
                  +-----+   +-----+
                     /     /  \   \
                    /     /    \   +--------------+
                   /     /      \                  \
  +------+     +--------+       +--------+       +--------+     +------+
  |client|-----| Leaf N |-------|TransitN|-------|Sender N|-----|server|
  +------+     +--------+       +--------+       +--------+     +------+

     |             | |         |    |                |             |
     |             |<|=========|====|== Video broadcast stream ====|
     |---EPG Req---|>|         |    |                |             |
     |<--EPG Rep---|-|         |    |                |             |
     |---Key Req---|>|         |    |                |             |
     |<--Key Rep---|-|         |    |                |             |
     |--- IGMP --->| |         |    |                |             |
     |             |-|--Auth-->|    |                |             |
     |             |<|---Auth--|    |                |             |
     |<-- IGMP ----| |         |    |                |             |
     |<============|=|=========|====|=== Video broadcast stream ===|
     |             | |         |    |                |             |

         Figure 2  sequence example of video broadcast service


3.4 Video on Demand Service

   Video on Demand Service is one of the streaming service which
   distribute streaming video data to single user on demand basis.
   Therefore, a user can enjoy watching video from start to end at
   any time he request.

   In this service, an original VoD streaming server is placed at
   central data center and it transmits streaming contents by IP
   unicast technology. And several mirror servers are placed at
   mirror sites which are located near the leaf nodes. To decentralize
   server's load, appropriate server is selected considering server's
   load and clients location.

   Multiple static P2P LSP are established between a sender nodes
   which accomodate original servers and all of the leaf nodes which
   accomodate broadcast receivers. As same manner, multiple LSP are
   established between a sender node which accomodate mirror servers
   and leaf nodes.

   In this service model, a NWA is introduced to guarantee QoS of video
   streaming traffic. A NWA constanly observe residual bandwidth of each



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   P2P LSP. Whenever NWA receive request for new video stream, NWA
   checks corresponding P2P and judge whether to accept this new session
   considering traffic demand.

   Because single P2P LSP convey multiple video stream, failure of this
   LSP cause severe QoS degradation. Therefore, Fast reroute technology
   [FASTREROUTE] is useful to guarantee transimission quality and attain
   reliable operation.

   Following figure shows one of the example of service sequence for
   video on demand service. In this example, a client request CPF of
   EPG. After passing authentication, client receive EPG from CPF.
   Selecting video channel, client request CPF of encryption decoder key
   and video server information (e.g. URL etc). This message is
   transffered to NWA. Then NWA judges whether to accept this request
   considering server load and corresponding P2P LSP load. After
   deciding to accept this request, NWA ask CPF to send back server
   information and encryption key to the client. Receiving these
   information, the client can control VoD server by RTSP and can
   receive video stream data.



                  +-----+   +-----+
                  | CPF |<=>| NWA |
                  +-----+   +-----+
                     /     /  \   \
                    /     /    \   +--------------+
                   /     /      \                  \
  +------+     +--------+       +--------+       +--------+     +------+
  |client|-----| Leaf N |-------|TransitN|-------|Sender N|-----|server|
  +------+     +--------+       +--------+       +--------+     +------+

     |             | |         |    |                |             |
     |---EPG Req---|>|         |    |                |             |
     |<--EPG Rep---|-|         |    |                |             |
     |-Ch.Info.Req-|>|         |    |                |             |
     |             | |-BW Req->|    |                |             |
     |             | |<BW Rep--|    |                |             |
     |<Ch.Info.Rep.|-|         |    |                |             |
     |-------------|-|---------|----|--- RTSP -------|-------------|
     |<============|=|======== |====|=== Video stream =============|
     |             | |         |    |                |             |

     Figure 3  sequence example of video on demand service






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3.5 Content Distribution Network architecture

   CDN must handle these three type of traffic within a single network
   and guarantee QoS of streaming data that are conveyed in both P2MP
   LSPs and P2P LSPs at the same time in a scalable, reliable fashion.

   Therefore, QoS control, TE and reliability control mechanism
   universal to both P2P and P2MP LSP are required. It is desirable that
   LSR in this CDN must handle both P2P and P2MP LSP at the same time.
   To share network resource flexibly, it is desirable that P2P and P2MP
   share same label space. And it is desirable that P2P and P2MP LSPs
   are established and maintenanced by same MPLS signaling protocol like
   RSVP-TE[RSVP-TE]. It is also desirable to use same Traffic
   Engineering Database (TED) for establishing CSPF P2P and P2MP LSPs.

4. Requirements for P2MP capability extension

4.1 P2MP LSP tunnels

   A P2MP LSP tunnel MUST be capable of carrying IP multicast traffic.

   As conventional P2P MPLS technology[MPLS-ARCH], packets are
   classified with FEC in this extension. And all packets which belong
   to a particular FEC and which travel from a particular node MUST
   follow the same P2MP path. A P2MP LSP MUST handle i) (S,G) multicast
   traffic, ii) ({S},G) multicast traffic, and iii) ({S},{G}) multicast
   traffic when transfering IP multicast with FEC.

   P2MP LSP has different dynamics compared with P2P LSP. Because
   destination leaf set changes frequently, it is RECOMMENDED to
   introduce a new session key other than destination IP addresses to
   identify a P2MP TUNNEL session.

4.2 P2MP LSP topology and Tree explicit routing

   Various optimizations in tree formation need to be applied to meet
   various needs such as bandwidth guarantees, delay requirements, and
   minimization of the total tree cost.

   The solution therefore MUST provide a means of establishing arbitrary
   trees. Figure 4 shows two typical examples.










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                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 tree                              SPF tree

                Figure 4 Examples of P2MP LSP topology


   One example is Steiner tree (Cost minimum tree). This tree is
   suitable for constructing cost minimum tree. From several evaluation,
   it turns out that steiner tree can reduce one half of necessary
   cost[STEINER]. To realize this tree, several intermediate node must
   be both MPLS data terminating node and transit node. This means that
   the node must perform both label swapping and decapsulation at the
   same time.

   This extension MUST support a mechanism that can setup terminate
   nodes between a sender node and leaf nodes.

   Another example is SPF tree. By using delay metric, one can calculate
   delay minimum tree. This tree is suitable for carrying real time
   traffic.

   To control tree toplogy this extension MUST support explicit routing
   mechanism [IPMCAST-MPLS] in tree manner. Expanding ERO function to
   indicate tree topology is one of this example. It is required that
   one can control P2MP tree topoloy any way by using this explicit
   routing mechanism.

4.3 Calculation of P2MP path

   P2MP path can be computed automatically or can be defined
   administratively by a network operator[MPLS-TE]. An administratively
   specified path can be completely specified or partially specified.

   A P2MP path is completely specified if all of the required branches
   and hops between a sender and leaf nodes are indicated. This P2MP
   path is calculated by offline management tool or CSPF engine
   implemtented in sender node. Considering CSPF calculation at sender
   node, it is RECOMMENDED to implement mechanism which can calculate
   whole P2MP path using information gathered by an underlying protocol
   such as IGP with traffic engineering extensions[OSPF-TE,IS-IS-TE].




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   A P2MP path is partially specified if only a subset of intermediate
   branches and hops are indicated. This specification include loose
   hop. In this case, it is RECOMMENDED to implement mechanism which can
   calculate expanded tree using information gathered by an underlying
   protocol such as IGP with traffic engineering extensions
   [OSPF-TE,IS-IS-TE] in branch node.

4.4 P2MP LSP establishment, teardown, and modification mechanisms

   This extension must support large scale P2MP establishment and
   teardown in a scalable manner.

   In addition to P2MP LSP establishment and teardown mechanism, it
   SHOULD implement partial tree modification mechanism. The graft and
   prune mechanism can be used to re-establish a partial P2MP LSP when
   the establishment of the subtree failed because it sometimes happens
   that the establishment of the subtree fails and the establishment of
   another part of the tree succeeds. It is inefficient in this
   situation for the whole P2MP LSP to be torn down and for the whole
   P2MP LSP to be re-established again.

   Re-establishment of a subtree whose establishment failed can be done
   using the graft and prune mechanism. The sender node or NMS that
   recognizes that the establishment of a subtree failed can
   re-calculate another P2MP route that avoids the failure point and can
   reach the leaf nodes. After this re-calculation, the sender node uses
   the graft mechanism for subtree re-establishment and uses the prune
   mechanism for subtree elimination. It is RECOMMENDED that this
   re-establishment does not cause any additional processing in nodes
   except along the path to the failure point, because the graft and
   prune process only affects those nodes.

   Joining/Leaving mechanism can be considered as part of
   Grafting/Pruning mechanism. Adding a leaf LSP to pre-established P2MP
   LSP can be considered as a subset of adding a subtree. Vice versa,
   deleting a leaf LSP from pre-established P2MP LSP can be considered
   as a subset of deleting a subtree.

   This extension SHOULD implement subtree Grafting and Pruning
   mechanism.


4.5 Management of P2MP LSP tunnels

   To identify established topology of P2MP LSP is very important for
   management purpose. A network operator uses this information to
   manage P2MP LSP. Therefore, topology information MUST be corrected
   and updated after P2MP LSP establishment and modification process.



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   For this purpose, conventional Record Route mechanism is useful.
   As same as conventional mechanism, this information should be
   forwarded to the sender node. This extension MUST support a mechanism
   which can correct and update tree topology information after P2MP LSP
   establishment and modification process. It is RECOMMENDED that those
   information are corrected in a data format by which the sendor node
   can recoginize tree topology without complicated data calculation
   process.

   The sender node SHOULD use this information to maintain the tree.

4.6 QoS control mechanism of P2MP LSP tunnels

   P2MP LSP share network resource with P2P LSP. Therefore it is
   important to use the same QoS control mechanism as P2P LSP for easy
   and scalable operation.

   This extension MUST support the same QoS indication mechanism as P2P
   MPLS. This extension MUST support FF and SE reservation style.

4.7 P2MP TE

   Frequent topological changes may occur in a P2MP LSP tunnel because
   it has many leaf nodes and a more complex topology.  Thus, traffic
   engineering is more important in a P2MP network environment than a
   P2P one. Traffic Engineering supports rerouting of an established TE
   tunnel. The route is decided according to the administrative policy.
   The detection of a more optimal path and network resource failure are
   examples of situations where path rerouting is needed.

   While TE tunnel rerouting is in progress, an important requirement is
   avoiding traffic disruption. A useful solution to this problem is the
   make-before-break concept. In this concept, traffic passes through
   the old path while the new rerouted path is being established. Once
   it has been established, traffic is switched to the new path and the
   old path is torn down. The make-before-break concept supports
   resource sharing of the common part where the old and new path cross.
   This sharing is useful to avoid competition between the resources of
   the two paths. Details of the make-before-break concept are given in
   RFC 3209. In the case of P2MP, there are cases where the
   topology of the area to be rerouted is a tree and there are many
   paths that should be rerouted when path rerouting occurs at once. So
   it is desirable that multiple paths are moved in one rerouting
   mechanism.

   This extension MUST supports the make-before-break concept for P2MP
   TE tunnels. It is deisrable to support local repair mechanism based
   on make-before-break but this is a topic for future study.



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4.8 IPv4/IPv6 support

   This extension MUST support both IPv4/IPv6 transmission.

4.9 P2P and P2MP LSP establishment

   This extension MUST support both P2P and P2MP LSP. The label space
   SHOULD be shared between P2P and P2MP MPLS. And link resource SHOULD
   be shared between P2P and P2MP MPLS. It is desirable to use same TE
   information gathered by IGP with traffic engineering extensions when
   CSPF engine calculate P2P and P2MP CSPF path.

4.10 Interworking function with IP multicast

   This extension MUST support interworking function with conventional
   IP multicast routing protocol such as PIM-SM[PIM-SM].

   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 sender to hold sufficient information in order to
   optimise multicast FEC on sender nodes.


5. Requirements for Service convergence network

5.1 CDN/VoIP/VPN service convergence network

   This extension must be applicable to CDN/VoIP/VPN service convergence
   network. Applicabilty to VoIP and VPN network is discussed in the
   future.

5.2 VPN Multicast

   It is RECOMMANDED that this extension must be applicable to VPN
   multicast network.

   To support VPN multicast, this extension MUST support Multicast
   routing information exchange mechanism between PEs. And this
   extension MUST support tunneling mechanism of multicast data and
   control traffic within a provider network. Detail mechanisms are
   discussed in the future.

6. Security Considerations

   Security considerations will be addressed in a future revision of
   this document.





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7. Acknowledgements

   The authors would like to thank George Swallow for his review and
   suggestion of an earlier draft of this document.

8. References

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

   [IGAP] T. Hayashi, D. Andou, H. He, W. Tawbi, T. Niki, "IGAP for user
   Authentication Protocol (IGAP)", draft-hayashi-igap-00.txt,
   January 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

   [FASTREROUTE] 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-01.txt, May 2003

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

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

   [IGMPv2] W. Fenner, "Internet Group Management Protocol, IGMP,
   version 2", RFC 2236, November 1997.

   [IGMPv3] Cain, B., "Internet Group Management Protocol,
   Version 3", draft-ietf-idmr-igmp-v3-11.txt, May 2002

   [PIM-SM] 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.

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

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




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

   [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.

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: yasukawa.seisho@lab.ntt.co.jp

   Ichiro Inoue
   NTT Network Service Systems Laboratories, NTT Corporation
   9-11, Midori-Cho 3-Chome
   Musashino-Shi, Tokyo 180-8585 Japan
   Phone: +81 422 59 6076
   EMail: inoue.ichiro@lab.ntt.co.jp





























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