By default, the switch fabric for the ERX-1440, ERX-310, E120, and E320 routers uses a bandwidth weighting ratio of 15:2 for multicast-to-unicast weighted round robin (WRR). In the absence of strict-priority traffic, and when both unicast and multicast traffic compete for switch fabric bandwidth, the switch fabric allocates 15/17ths of the available bandwidth to multicast traffic and 2/17ths of the available bandwidth to unicast traffic.
The fabric weights command enables you to specify a ratio for multicast-to-unicast traffic on the router switch fabric. The no version of the command reverts the weighting ratio back to its default.
fabric weights
- host1(config-traffic-class)# fabric weights
multicast 2 unicast 1