A PROTOCOL FOR SCALABLE LOOP-FREE MULTICAST ROUTING

In network multimedia applications such as multiparty teleconferencing , users often need to send the same information to several (but not ne cessarily all) other users, To manage such one-to many or many-to-many communication efficiently in wide-area internetworks, it is imperativ e to support and perform multicast routing, Multicast routing sends a single copy of a message from a source to multiple receivers over a co mmunication link that is shared by the paths to the receivers, Loop-fr eedom is an especially important consideration in multicasting because applications using multicasting tend to be multimedia and bandwidth i ntensive, and loops in multicast routing duplicate looping packets. We present and verify a new multicast routing protocol, called multicast Internet protocol (MIP), which offers a simple and flexible approach to constructing both group-shared and shortest-paths multicast trees, MIP can be sender-initiated or receiver-initiated of both; therefore, it can be tailored to the particular nature of an application's group dynamics and size, MIP is independent of the underlying unicast routin g algorithms used, MIP is robust and adapts under dynamic network cond itions (topology or link cost changes) to maintain loop-free multicast routing, Under stable network conditions, MIP has no maintenance or c ontrol message overhead, We prove that MIP is loop-free at every insta nt, and that it is deadlock-free and obtains multicast routing trees w ithin a finite time after the occurrence of an arbitrary sequence of t opology or unicast changes.