Abstract: Aiming at the problems that it is difficult to build an optimal multicast tree and its convergence is slowly in layer 2 Ethernet, a new optimal multicast tree construction method is proposed in this paper. This method put IS-IS protocol to compute the shortest path tree for layer 2 Ethernet. By means of the Code-Length-Value(CLV) of expanded link-state bag to improve its notice mechanism, an optimal multicast tree can be easily construct. The optimal multicast tree can be reconstructed fast when network topology changed. Test results show that the method can make the time of multicast tree convergence be reduced from 10 s~20 s to 50 ms and ensure that the tree is an optimal multicast tree.

Key words: multicast tree, Multiple Spanning Tree Protocol(MSTP), Internet Group Management Protocol(IGMP) snooping, IS-IS routing protocol

摘要： 针对二层以太网难以构建最优组播树且收敛速度慢的问题，提出一种新的最优组播树构建方法。该方法将IS-IS协议用于二层以太网络最短路径树的计算，通过扩展链路状态包的CLV改进其通告机制，以便构建最优组播树，且网络拓扑发生变化时可快速重构此最优组播树。测试结果表明，该方法可将组播树的收敛时间从现有方法的10 s~20 s缩短到50 ms，并能确保该组播树为最优组播树。

关键词: 组播树, 多生成树协议, IGMP侦听, IS-IS路由协议

CLC Number: 

• TP393