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

Suresh BoddapatiVenu Hemige

Sunil KhandekarVach KompellaMarc Lasserre

Rob NathRay Qiu

Yetik SerbestHimanshu Shah

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

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 IGMP+PIM.• Requires CEs to disable PIM Join-Suppression.

• For PWs, PEs learn PIM states using:– PIM Snooping OR

– Via LDP.

What changed from

draft-serbest-l2vpn-vpls-mcast-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-

vpls-mcast-ldp-00.• Modified procedures for duplicate traffic.

PE1

Server

PE3

PE2

R3 R4

R2R1

PW

AC

Join to RPF Nbr

Join seen

Data Traffic

Traffic sent only on interested ports

Joins flooded.

Only PEs towards RPF build state

PIM-Snooping Basic Example

PE1

Server

PE3

PE2

R3 R4

R2R1

PW

AC

Join to RPF Nbr

Join seen

Data Traffic

Duplicate Traffic Scenario

Duplicate traffic to both R3 and R4

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

PE1

Server

PE3

PE2

R3 R4

R2R1

PW

AC

Join to RPF Nbr

Join seen

Data Traffic

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

PIM ASSERT

Assert Mechanism in VPLS PIM-Snooping

Assert Winner becomes the forwarder in the VPLS

AC1

PW12

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.