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BGP Point-to-Multipoint LSP

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					BGP Point-to-Multipoint LSP
       draft-satoru-mpls-bgp-multipoint-02

Satoru Matsushima (satoru@ft.solteria.net)
Tetsuya Murakami (tmurakam@cisco.com)
 Kenichi Nagami (nagami@inetcore.com)
               Motivation
• Expand P2MP-LSP enabled area
  – Cover non-TE area
  – Cover non-MPLS area and inter-work w/
    MPLS p2mp-lsp
  – Inter-AS/Domain p2mp-lsp
• BGP is applicable for these motivations
                 Requirements
• Discover/Notify P2MP capable branch and egress
  nodes
   – Applicable for any P2MP signaling protocol
   – Inter-Domain P2MP LSP
• P2MP LSP can be used over P2P/MP2P LSP
   – Migration and co-existing scenarios
• Policy based P2MP tree decision
   – Per LSP basis
Overview of BGP for P2MP LSP

                               Advertising P2MP-LSP=L         Advertising P2MP-LSP=L
   Advertising P2MP-LSP=L      w/ brach-LSR-b                 w/ branch-LSR-b and c




   Ingress                  Branch                   Branch                    Egress
   LSR-a                    LSR-b                    LSR-c                     LSR-d




     Joined P2MP-LSP=L               Joined P2MP-LSP=L             Joined P2MP-LSP=L
     Upstream LSR=a                  Upstream LSR=b                Upstream LSR=c
     Label = C                       Label = B                     Label = A
BGP P2MP-LSP example
                        Sender


             Ingress
              LSR1


             Branch
             LSR2



                          Branch                       Egress
    LSR3
                          LSR4                         LSR7


   Egress                 Egress
                                               Receiver3
   LSR5                   LSR6
                                                                 P2P-LSP

            Receiver1              Receiver2                    P2MP Instance
                       Proposal
• New BGP attribute
  – P2MP_ID (ext community)
     • Identify the P2MP_LSP
  – P2MP_BRANCH_LIST (ext community)
     • Indicate the branches which traverse P2MP_LSP
     • Detecting and protecting loop
  – P2MP_IMPORTED_BRANCH (ext community)
     • Indicate the upstream branch of downstream LSR (JOIN)
  – NLRI
     • Distinguish ingress and each branches uniquely even if in same
       LSP
     • Label distribution from downstream LSR
     Data plane of BGP P2MP
• P2MP instance
  – The entity of replication and stitching P2P/MP2P LSP
  – BGP makes policy of which is upstream/downstream
    for each P2MP LSP
• Other P2MP signaling can be used
  – Data plane is separated as P2MP instance
  – RSVP and LDP may use BGP as find p2mp capable
    node
  – Inter-work w/ BGP P2MP-LSP
                 Current status
• Deployment
  – Current MPLS network co-existing w/ this solution is
    working
  – Validating attribute and behavior
• Problem
  – Defining a NLRI for P2MP AFI/SAFI is needed
     • Currently, vpnv4 is used to distinguish p2mp LSP
     • To keep bgp modularity and protecting miss behavior w/
       MPLS-VPN
                  Next step
• Good start point to develop BGP based
  P2MP discussion
  – Interest for this work?
• Adopt as WG item?
• Please send your comment to the list

				
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