3Com 2500 Switch User Manual


 
5-6 CHAPTER 5: ROUTING WITH IP MULTICAST
Rate Limit The rate limit determines how many multicast packets can travel over the
interface in kilobytes-per-second. The LANplex system drops multicast traffic
that travels faster than this rate. The default is set to 0, which implies no rate
limit is set. In all other instances, the lower the rate limit, the more limited
the traffic over the interface.
Multicast Tunnels Multicast tunnels are logical connections between two multicast routers
through one or more unicast routers. The multicast router at the local
endpoint of the tunnel encapsulates multicast packets in a format that
unicast routers can interpret and forward. The multicast router at the
remote endpoint decapsulates the packets into their multicast format.
Tunnels are virtual links through the unicast IP network.
Multicast tunnels have characteristics similar to those of a multicast
interface: a DVMRP metric value, a TTL threshold, and a rate limit. When you
define a multicast tunnel, you also specify the destination address of the
remote multicast router that is the remote endpoint of the tunnel.