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MVPN PE-PE Signaling. IETF 64 Nov 2005 Nidhi Bhaskar/Yiqun Cai/Gargi Nalawade. PE-PE signaling for Multicast VPNs. Multicast VPN PE-PE signaling defined using PIM LAN procedures Push for replacing PIM with BGP Aim to describe the required protocol changes and analyze the impact on BGP/PIM.
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MVPN PE-PE Signaling IETF 64 Nov 2005 Nidhi Bhaskar/Yiqun Cai/Gargi Nalawade
PE-PE signaling for Multicast VPNs • Multicast VPN PE-PE signaling defined using PIM LAN procedures • Push for replacing PIM with BGP • Aim to describe the required protocol changes and analyze the impact on BGP/PIM
Enhancements required in BGP draft-nalawade-l3vpn-mcast-signaling-bgp-00.txt • Multicast PE-PE (Overlay) SAFI NLRI - {RD:G:Flags:S/RP:U-PE:D-PE} • RT/RD Import/Export • Filtering • PIM/BGP Interaction • Inter-AS • New functions in BGP like aggregating D-PE, U-PE based filtering, RPF lookup on ASBR and probably others. No extensions for Unicast Reachability. Rely on existing VPNv4 Unicast for that.
CE-2 CE-4 Receiver1 Source = 1.1.1.1 RR BGP State: RD:232.1.1.1:SPT:1.1.1.1:PE-4:PE-2 RD:232.1.1.1:SPT:1.1.1.1:PE-4:PE-3 RD:232.1.1.1:SPT:1.1.1.1:PE-4:Label200… Transit for VPN SSM - BGP PE-2 BGP State: RD:232.1.1.1:SPT:1.1.1.1:PE-4:PE-2 RD:232.1.1.1:SPT:1.1.1.1:PE-4:Label200… PE-4 BGP State: RD:232.1.1.1:SPT:1.1.1.1:PE-4:PE-2 RD:232.1.1.1:SPT:1.1.1.1:PE-4:PE-3 RD:232.1.1.1:SPT:1.1.1.1:PE-4:Label200… RR PE-1 PIM-V4 VRF JOIN:1.1.1.1,232.1.1.1 e0 e1 PIM-V4 VRF JOIN:1.1.1.1, 232.1.1.1 PE-2 PE-4 PE-3 PE-3 BGP State: RD:232.1.1.1:SPT:1.1.1.1:PE-4:PE-3 RD:232.1.1.1:SPT:1.1.1.1:PE-4:Label200… e0 CE-3 Receiver2
BGP - Multicast Routing State • RR Stores 1 multicast route as N*NLRI where N is #of D-Pes interested in stream. And stores all mroutes in the AS. • Multicast J/P or route change frequency is different from unicast. Potential load on RR processing a large number of multicast route changes. Has latency implications for multicast. • If there are “N” messages/minute on “M” PEs, RR processes “N*M” messages/minute.
BGP <-> PIM Futures/Open Issues PIM State machine changes to interact with BGP. • No PIM hellos for option negotiation. Might be good to allow options to be carried in BGP. • No Join suppression or Prune override in PIM. Requires explicitly tracking downstream joiners in either PIM or BGP. • No support for Bidir DF Election. • No support for PIM Assert resolution.
BGP <-> PIM Futures/Open Issues • PIM-SM shared tree pruning. Cannot preserve the full state nature of (*,G),(S,G,R) prunes in BGP. NLRI are not “associated” with each other => Re-flooding of the shared tree for pruned sources. • BSR mappings require “full state update” as well. • G/mask, RP1, RP2, RP3… For proper operation PIM needs all three RPs before it can make a decision based on the mapping. • Mappings carry holdtimes/priorities for RPs, where to put these, BGP attributes ?
BGP Futures/Open Issues… • BGP will not restrict Binding state to multicast tree. • Not enough bits to encode SAFI length for IPv6!!