一个适用于广域网的可靠多对多广播通信协议的设计与分析

THE DESIGN AND ANALYSIS OF A MULTIPLE TO MULTIPLE RELIABLE MULTICAST PROTOCOL FOR WAN

提出并实现了一个适用于广域网络环境下允许大量网络节点参加的“多对多”可靠广播通信协议：基于发送方的分组可靠Ｍｕｌｔｉｃａｓｔ协议——ＳＩＧＲＭＰ．该协议能在不影响通信系统传输时延和报文吞吐率前提下，成功地避免应答报文拥塞现象，为Ｉｎｔｅｒｎｅｔ网络上参与广播通信的节点提供“可靠”而“有序”的“多对多”广播传输服务；给出了Ｍｕｌｔｉｃａｓｔ通信的性能分析和测试结果；编程实现了一个简单的分布式虚拟环境（ＤＶＥ）演示系统．

The main topic of this paper is the multiple to multiple reliable multicast protocol for WAN environment. A new protocol, the Sender initiated Grouping Reliable Multicast Protocol (SIGRMP), is proposed. The SIGRMP protocol guarantees the transmission reliability for the multiple to multiple multicast communication on the Internet. It is based on a novel concept, that is the Multicast Grouping (MG). All participants in a large scale multicast system are divided into several groups, and in each group there is a special node (the Multicast Group Trustee, MGT) that is responsible for the packet reliable transmission among the group. According to the partition method, each entity is required to multicast its entity state PDUs only among its interesting subgroups rather than the whole system, without affecting the whole system's ongoing session. Thus it reduces the CPU processing time and the network traffic dramatically. The SISGMP transmission reliability is based on the sender initiated approach. The SIGRMP protocol successfully gets over the ACK implosion for the multicast systems without sacrificing the communication delay and throughput heavily. On the same time, the reliable unicast and one to multiple multicast transmission services are also supported. The performance analysis approach to multicast system is also given. The results of analysis and test show that the proposed protocol is high effective and practical. The SIGRMP protocol was implemented and tested on the Internet environment, a simple DVE demonstration system based on the SIGRMP protocol was designed and implemented. The DVE system can run on several SGI workstations connected by Internet.