1. Multicast Pruning for PBB-VPLS
Draft-sajassi-l2vpn-pbb-vpls-multicast-00.txt
July 28, 2008

2. Authors
Ali Sajassi
Luyuan
Pradosh Mohapatra
Nabil Bitar
Raymond Zhang

3. What is it ? PBB-VPLS provides much improved scalability for
C-MAC addresses
# of VPLS instances and its associated PWs
C-MAC scaling is provided by encapsulating many C-MACs in a B-MAC address
VPLS/PW scaling is provided by using a single VPLS for many I-SIDs
However, when a VPLS is used for many I-SIDs, then we need to limit the scope of broadcast per I-SID (e.g., per customer)
This draft describe the use of BGP for limiting the scope of broadcast per I-SID (e.g., multicast pruning per I-SID)

4. What is it ? – cont. MPLS Core PE PE Customer Network (802.1Q)
Customer Equipment
Access Network (802.1ah)
Access Network (MPLS)
IB- BEB
BCB
BCB
u-PE w/ IB-BEB PB PB CE PE
IB- BEB
BCB PE
u-PE w/ IB-BEB PB PB PE

5. Why is it needed ?
If multicast pruning is not performed, then multicast/ broadcast traffic of a given customer can be replicated and sent to receivers that have no interest in the data resulting in
Unnecessary processing & BW consumption at the ingress PE
Unnecessary BW consumption in the network
Unnecessary processing at the egress PE

6. How it works ?
Since these multicast B-MAC addresses are administratively configured (directly or indirectly), use BGP to “auto-discover” them
A given PE that is administratively configured for a multicast B-MAC address, discovers what other PE devices are interested in this multicast group
It then creates an OIF list corresponding to these PEs
The multicast frames (for a given I-SID) are replicated only over the PWs associated with these PE devices

7. How it works ? – Cont.
Define a new BGP NLRI called PBB-VPLS NLRI as follow:
RD (8 octets)
VE-ID of VSI (4 octets)
B-MAC address (6 octets)
Use AFI of 25 (L2VPN AFI) and a new SAFI for PBB-VPLS
Use a new BGP attribute called PMSI Tunnel Attribute as defined in [MVPN-BGP-Encode] and [L2VPN-Mcast] to indicate “ingress replication” is used for this NLRI.

8. Advantages
Extending the existing auto-discovery for this propose which MPLS providers are already familiar with
Avoiding using any IEEE protocols for the MPLS core !!

9. Next Step Solicit comments on the mailing list
Ask for WG status by next IETF meeting