Multicast replication using dual lookups in large packet-based switches

We present a scheme using dual lookups to replicate multicast packet with no loss occurring for large IP routers with as many as 128×128 output ports. We are motivated by the fact that the length of multicast destination identifier (MDI) attached to each multicast packet is inadequate to specify exactly the subset of the output ports for the ever increasing number of multicast connections to be supported. We first present our switch fabric suitable for packet-based switches in large routers, and then give the proposed scheme charactered as dual lookups and three-stage replications. Experiment results obtained by using a real terabit router called SR1880-T which has adopted the scheme are given to verify the scheme.