Simulation-Based Research On IGMP And Its Enhancement

With the rapid development of information and Internet technologies, the multimedia network technology has been becoming the hot topic that draws people's great attention. Nowadays, The multimedia network technology has been applied in many fields. However, it also poses a real challenge to the existing network structure. Since the transmission of streaming media has high demands over the throughput and delay of the network, the unicast and broadcast can never support it. Ip multicast is a data transmission method that used to deliver data from one or more soures to many other interested recipients. The multicast data can answer the demands of great amount of clients with very low bandwidth occupation. As a result, Ip multicast can transport multimedia data effectively and is becoming the key technology in multimedia application field.At the other hand, the network, especially the large-scale communication network always has a very complex structure. All the integration of different networks, the increasing of the classes of service and the emerging of new network technologies make network simulation become a important method in network design, testing and application research. NS-2 is a wide used professional software for network simulation. It's free, open-source and mainly applied under Linux operation system (it can also works under Windows, Unix, Macintosh OS). Since many network protocols, classes of service, queuing management methods and routing algorithms have been realized in NS-2 and the advantages in scalability, rapidity and efficiency, the researchers can take out network technology development easily using NS-2.In this thesis, we first have a global overview of the IP multicast related technologies, and then made a deep analysis about the existing multicast realization method in NS-2 based on a good understanding of its framework and work mechanism. We point out the shortages of the existing multicast mechanism, specifically, there is just a simple group management method in NS-2 and without the realization of Internet Group Management Protocol(According to our investigation, it has never been realized in the multicast mechanism of the network simulation softwares of this like). In response to this lack, we have made a protocol expanding in the original multicast mechanism of NS-2 according to IETF's IGMPv3. Besides, in the traditional IP multicast group management, where any host can join a multicast group and obtain the multicast data by sending an IGMP access application, which bring out uncontrollability problem to the communications quality of service. So we made a further research on the performance measurement(such as payload, delay, loss-rate and the remained bandwidth resources) based on the expended multicast mechanism, put forward and realized a new QoS-oriented group management mechanism preliminarily. The realization of IGMPv3 expanding and the QoS-oriented group management mechanism in NS-2 will have great research value in the future network simulation, especially the multicast network simulation.