一种融合MAC层拥塞通告的混合网络TCP协议

An improved TCP with cross-layer congestion notification over wired-wireless hybrid networks

在研究无线网络媒体接入控制(MAC)层拥塞测度的基础上,提出了一种跨层的显式拥塞通告(ECN)机制,即:当数据包中记录的请求发送(RTS)次数超过给定阈值时,通过ECN向传输控制协议(TCP)源端发送拥塞通告,从而启动TCP拥塞控制。这种跨层设计是对有线网络中基于主动队列管理(AQM)的拥塞控制的有效补充,由此可以得到一种与已有的协议无缝连接的混合网络TCP模型。通过在网络模拟器NS2中构造多流无线局域网和多跳无线/有线混合网络,对所提出的方法进行了仿真,实验结果说明该方法能够提高混合网络的性能,并且具备良好的扩展性。

This paper proposes an cross-layer ECN （explicit congestion notification） scheme, based on the research of congestion metrics from the media access control （MAC） layer over wireless networks, under which, the TCP sender can trigger congestion control by ECN if the RTS （reques to send） count in its receiving packet exceeds a given thresh. This crosslayer design is an efficient enhancement to the congestion control based on the active queue management （AQM）, with which a model of coupling existing TCP over wired-wireless networks can be obtained. To verify the new TCP model, some wireless local area networks including multi TCP flow and multi-hop wireless/wired hybrid networks were designed in NS2. The simulation results show that the method can improve the network performance and can be easily extended to other TCP variants.