应用层组播树分裂恢复算法研究

Maintenance algorithm of application level multicast tree

应用层组播树是由终端用户构造而成,其稳定性不能得到保证。由于终端用户失效导致组播树分裂,产生多个分支,因此需要快速恢复组播树,保证各组用户接收到组播数据。分析组播树分裂恢复特点,构造了带有时延和度约束的组播树分裂恢复问题数学模型。利用拉格朗日松弛方法分解此复杂问题,提出一种新的应用层组播树分裂恢复算法。仿真实验表明,此算法具有较快的收敛速度,而且算法稳定。

The application level multicast tree is composed of the end hosts which can not ensure the stability of the multicast tree. The failure of the end host in the multicast tree may cause the split of the multicast tree. Therefore, the multicast tree needs to be rebuilt quickly to ensure that every group of clients in the mulficast tree can receive the data. Analyzing the characteristics of the division and renewal of the mulficast tree, the maintenance model of the application level multicast tree with the delay and degree constraints was constructed. The complicated multicast tree problem was decomposed by Lagrangian relaxation. A new maintenance algorithm of the application level multicast was advanced. The simulation results show that the algorithm is of higher converging speed, stability and easy operation.