Abstract: The paper introduces some problems of TCP in high bandwith delay product network and gives two method to solve these questions.One is only to update the endpoint protocol such as HighSpeed TCP, the other is a new mechanism such as XCP protocol, which needs router to update the feedback of each packet. The paper simulates these three protocols and finds that XCP has the best performance of three protocols except the difficulty of deployment, increasing of router load and much additional informations in the packets

Key words: High bandwidth delay product (High BDP); XCP; HighSpeed TCP

摘要： 介绍了TCP 协议在大带宽时延积网络(High BDP)环境中存在的问题，论述了High BDP 网络环境中目前存在的两种解决拥塞控制的方法，一种是只修改端节点拥塞控制协议如HighSpeed TCP，另一种是需要路由器进行速率协同调整的机制，如XCP 协议。然后对比三者在瓶颈链路利用率、公平性、TCP-Friendly、动态特性等指标上的性能，仿真结果表明XCP 在这些性能指标上优于前两者，但同时在分组中增加了更多信息，增加了路由器的工作负荷以及布置困难。

关键词: 大带宽时延积；显式控制协议；高速TCP