Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net 1 Multicast in VPLS draft-raggarwa-l2vpn-vpls-mcast-00.txt Rahul Aggarwal (Juniper) Yuji Kamite (NTT) Luyuan Fang (AT&T)

2 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net Co-Authors  Yakov Rekhter (Juniper)  Chaitanya Kodeboniya (Juniper)

3 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net Agenda  Update since last IETF  Limitations of existing VPLS proposals for Multicast  VPLS Multicast Architecture – where do the various drafts fit  Avoiding PIM snooping on the PWs  Use of P-Multicast Trees  Conclusion

4 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net Update Since Last IETF  Part of the work was presented in this WG at the last IETF when it was part of draft-raggarwa-l3vpn- mvpn-vpls-mcast-01.txt  The VPLS mechanisms are now in a separate new draft as per WG feedback

5 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net Current VPLS proposals:  “ Virtual Private LAN Service” ( draft-ietf-l2vpn-vpls- bgp )  “ Virtual Private LAN Services over MPLS ” ( draft-ietf- l2vpn-vpls-ldp )  Limitations of these proposals for VPLS multicast…

6 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net Limitations of current VPLS proposals for VPLS Multicast  Do not allow the use of P-Multicast Trees for VPLS multicast data traffic Desirable for optimizing bandwidth efficiency  PEs with VPLS sites that do not have receivers in a given multicast customer (S, G) receive traffic for that multicast stream  Focus on optimizing state and not bandwidth.

7 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net Design Objectives for multicast support in VPLS service (not a complete list)  A given customer (multicast) packet should traverse a given service provider link at most once  Deliver customer multicast traffic to only PEs that have (customer) receivers for that traffic  Deliver customer multicast traffic along the “optimal” paths within the service provider (from the ingress PE to the egress PEs) The amount of state within the service provider network required to support Multicast in VPLS service should be no greater than what is required to support unicast in VPLS service The overhead of maintaining the state to support Multicast in VPLS service should be no greater than what is required to support unicast in VPLS service Optimize Bandwidth: Optimize State: Optimizing Bandwidth and State are conflicting goals

8 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net VPLS Multicast Architecture Control Plane  VPLS Auto-Discovery Use existing VPLS auto-discovery mechanisms  Allow elimination of flooding PE-CE snooping – draft-serbest-l2vpn-vpls-mcast In VPLS a PE does not maintain a layer 2 adjacency with a CE PE-PE reliable exchange of multicast control messages Allow avoiding PIM-IGMP snooping overhead on PWs PIM with reliability extensions or BGP Draft-raggarwa-l2vpn-vpls-mcast-

9 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net VPLS Multicast Architecture Data Plane Ingress Replication Separate Tree for Every C-(S, G) Separate Tree per-set-of VPLSs “Inclusive Mapping” Separate Tree per-set-of C-(S, G)s “Selective Mapping” Increasing P-router state and Bandwidth efficiency State = Unicast VPLS Unbounded State Aggregate State Tree = PIM, RSVP-TE P2MP LSPs, Receiver Initiated P2MP LSPs Decreasing P-router state and Bandwidth efficiency

10 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net PIM snooping – implications on the state maintenance on PE routers  PE router has to maintain (S, G) state at least for all the (S,G) received from all the local CEs E.g., assume PE with 1,000 CEs/sites, each VPLS site has at any given point in time on average receivers for 3 groups, PE has to maintain at least 3,000 (S,G) entries  PE router maintains (S, G) state by processing PIM Join messages received from (a) all sites of VPLSs connected to that PE, AND (b) all the remote PEs that have members of these VPLSs E.g., assume PE router with 1,000 CEs/sites, each VPLS site has at any given point in time on average receivers for 3 group, each group is present on average in 10 sites, PE router has to process ~300 PIM Join per second, and ~900 (S, G) entries per second in a steady state due to periodic PIM Join and PIM Join suppression

11 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net Avoiding PIM Snooping on PWs Reliable Exchange of Multicast Control Messages between PEs PE 1 CE-B2 CE-B3 PE 3 PE 2 PE 4 VPLS A Site 3 CE -A1 CE-B1 CE-A2 CE-A4 CE-A3 VPLS B Site 1 VPLS B Site 2 VPLS A Site 4 VPLS B Site 3 VSI-A VSI-B VRF-B VPLS A Site 2 VPLS A Site 1 VSI-A RR PEs have I-BGP Peering Only With the RR C-S -> C-G PIM Join C-S, C-G – Snooped at PE1 BGP MVPN Routing Information Update: <RD, C-S, C-G, Originator PE – PE1 Upstream PE – PE2, RT>

12 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net VPLS Multicast Data Plane Tunnels  SP Multicast Trees Draft-raggarwa-l2vpn-vpls-mcast Aggregate Trees (Inclusive Mapping) Aggregate Data Trees (Selective Mapping) Use PE-CE snooping and PE-PE Reliable multicast message exchange  Ingress Replication Existing VPLS proposals AND PE-CE snooping and PE-PE Reliable multicast message exchange

13 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net Aggregate P-Multicast Trees  Allow one P-multicast Tree to be shared across multiple VPLSs  Can be setup using PIM or P2MP MPLS TE No architectural limitation on the P-multicast tree technology  Requires a MPLS label to demultiplex a particular VPN ‘Upstream’ label allocation by the root of the tree Egress PEs maintain a separate label space for each P- multicast tree root  State grows less than linearly with number of VPLSs Some efficiency of multicast routing may be sacrificed

14 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net VPLS Multicast Data Plane P-Multicast Trees (Inclusive Mapping) PE 1 CE-B2 CE-B3 PE 3 PE 2 PE 4 VPLS A Site 3 CE -A1 CE-B1 CE-A2 CE-A4 CE-A3 VPLS B Site 1 VPLS B Site 2 VPLS A Site 4 VPLS B Site 3 VSI-A VSI-B VPLS A Site 2 VPLS A Site 1 VSI-A RR VPLS Membership Discovery: eg PE1 C-S -> C-G Aggregate Tree – PE2 as Root BGP Signaled VPLS – Tree Binding:

15 Copyright © 2004 Juniper Networks, Inc. Proprietary and Confidentialwww.juniper.net Conclusion  Comments ?