PIM Snooping in VPLS draft-hemige-serbest-l2vpn-vpls-pim-snooping-00.txt

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PIM Snooping in VPLSdraft-hemige-serbest-l2vpn-vp
ls-pim-snooping-00.txt

• Suresh Boddapati
• Venu Hemige
• Sunil Khandekar
• Vach Kompella
• Marc Lasserre
• Rob Nath
• Ray Qiu
• Yetik Serbest
• Himanshu Shah

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Background

• WG consensus from last IETF split VPLS
  Multicast into
• Mcast Trees in Provider Core (draft-raggarwa-l2vpn
  -vpls-mcast)
• IGMP-Snooping (draft-ietf-magma-snoop-12.txt )
• PIM-Snooping in VPLS
• PE-to-PE Mcast State Distribution
• Split draft-serbest-l2vpn-vpls-mcast-03 into
• PIM-Snooping in VPLS (This draft)
• PE-to-PE Mcast State Distribution in VPLS using
  LDP

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PIM Snooping in VPLS

• VPLS floods mcast traffic today.
• PIM-Snooping prevents unwanted mcast traffic
• Issue A of the Requirements Draft.
• PIM Snooping on ACs.
• Defines data forwarding rules for IGMPPIM.
• Requires CEs to disable PIM Join-Suppression.
• For PWs, PEs learn PIM states using
• PIM Snooping OR
• Via LDP.

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What changed from draft-serbest-l2vpn-vpls-m
cast-03?

• Removed IGMP-Snooping
• Updated PIM-Snooping procedures.
• Requires CEs to disable PIM Join Suppression.
• PIM Join/Prunes are flooded in VPLS.
• LDP procedures moved to draft-qiu-serbest-l2vpn-vp
  ls-mcast-ldp-00.
• Modified procedures for duplicate traffic.

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PIM-Snooping Basic Example
R2
R1
PE2
PE1
Joins flooded. Only PEs towards RPF build state
Traffic sent only on interested ports
PE3
PW AC Join to RPF Nbr Join seen Data Traffic
R4
R3
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Duplicate Traffic Scenario
R2
R1
PE2
PE1
Duplicate traffic to both R3 and R4
PE3
PW AC Join to RPF Nbr Join seen Data Traffic
R4
R3
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Assert Mechanism in VPLS PIM-Snooping

• Constraint Split-Horizon rules require traffic
  ingressing on PW to not egress on PW.
• Facilitate traffic to reach the routers
  forwarding traffic.
• Results in Assert between the routers.
• Two rules facilitate this
• Add incoming port to outgoing-port-list
• When Join is seen, add PW towards RPF-neighbor
  to outgoing-port-list

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Assert Mechanism in VPLS PIM-Snooping
R2
R1
AC1
PIM ASSERT
PE2
PE1
1. A PE snooping a Join(S,G) adds IIF and OIF to
OIF-List. 2. A PE seeing a Join, adds the PW to
the RPF-nbr to the OIF-List
PW12
PE3
PW AC Join to RPF Nbr Join seen Data Traffic
Assert Winner becomes the forwarder in the VPLS
R4
R3
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Summary

• PIM-Snooping is important to make VPLS Multicast
  work.
• There is a lot of interest in solving the issue
  addressed by this draft.
• WG document.