Sender-initiated multicast forwarding scheme

We propose a sender-initiated multicast (SIM), specifically designed for small group communications such as teleconferencing and file distribution. Contrary to traditional IP multicast, SIM reduces the cost of allocating a global multicast address by attaching receiver addresses to the packet header. SIM routers route packets according to these addresses; therefore, the cost of the control traffic between routers can be lessened by applying the existing unicast routing table. The key feature of SIM is its preset mode, which uses SIM forwarding information base (FIB) entries on routers to achieve cost-efficient packet forwarding. Another feature is an automatically created SIM tunnel, which provides the ability to maintain SIM FIB only on routers that act as multicast branching points. We describe the SIM mechanism in detail, and present results evaluated through simulations. We show how SIM can achieve low cost in maintaining state information, cost-efficient packet forwarding, and incremental deployment.