移动IP中提高TCP性能的研究

Improvement of TCP performance in mobile IP

为了改善移动IP中TCP的性能,结合SNOOP协议和显式坏状态通告EBSN思想,设计了一种新的移动IP模型SBTCP.该模型在基站和移动主机的网络层进行了改进,使其能监测过往分组,在无线链路丢包时进行本地恢复同时延长发送方定时器,在通信对端增加了状态监测通告的机制,从而解决了本地恢复时的冗余重传、连接中断时的连续超时等问题,避免了由于无线链路及终端移动等因素造成的TCP性能的不必要下降.

Combining the SNOOP protocol and the idea of explicit bad state notification （EBSN）, a new mobile IP model- SBTCP is designed to improve the transmission control protocol（TCP）＇s performance. In this model, both base station and mobile node＇s network layers are reconstructed to inspect packets between them. Local recovery can be done when packets＇ loss occurs in wireless link and sender＇s timer is prolonged. The mechanism of state notification is added in correspondent＇s node. Therefore the problem of repeated retransmission in local recovery and continuous overtime when connection interrupted can be solved in this new model, thereby avoiding unnecessary decline of TCP performance due to wireless link and mobility.