The Research And Realization Of The Distance Vector Multicast Routing Protocol

IP Multicast provides an effective mechanism for communication and transmission. It can fully make use of the resource of the network, optimize the performance of the network and enable some distributed applications, which can't be realized by unicast or broadcast. IP Multicast is broadly used in many areas such as teleconferencing, audio/video broadcast, stock market issue, distance education, computer supported cooperate work etc. In this thesis, the DVMRP (Distance Vector Multicast Routing Protocol) is studied thoroughly. The main function and the configuration management of the protocol are realized based on the Net/3. At the beginning of the thesis, the theory of the multicast is introduced, and then the theory of DVMRP protocol and the how to forward the packets are analyzed detailedly. The protocol is realized in four modules, interface and neighbor module, routing module, graft/prune module and timer module. The main function of the interface and neighbor module is to initialize and age the interface, maintain the local group members, send and receive probe packets. When it is come to the graft/prune module, it is to maintain the message of pruning state, send and receive graft/prune packets, age the message of pruning state. As to the routing module, it is to initialize and age the routing table, send and receive the routing packets. The last module is the timer module, which is to add a timer, delete a timer, and activate the functions when the time is up. At the same time, the configuration management of the protocol are realized to config the protocol, show the message of running and debugging.