Load Sharing of Multicast Traffic by MCT-Cluster on CCEP Links

MCT peers load-share multicast traffic on both the local and the remote CCEP links when both are available.
Loads are only shared and may or may not be balanced across the CCEP links. An MCT peer selects a stream for forwarding based on a software hash function that uses the source and group addresses. You can have one MCT peer forwarding more multicast streams than another.

The load is assigned without regard to the capacity of the CCEP links, so MCT works best when both CCEP links have the same capacity and the source and group addresses are evenly distributed. This situation avoids the timing synchronization between the MCT peer routers, which would be very hard to achieve.

The sharing is done at the stream level (not the packet level) using the following software hash algorithm:

((source address + group address) & 0x00000001) ^ ((local_bridge_id > remote_bridge_id))

If the result is 1, the local CCEP forwards the traffic; if the result is 0, the remote CCEP forwards the traffic.

Parent topic: PIM Over MCT Intermediate Router Functionality