针对异构网络存在的高误码率和不对称带宽等特点使TCP性能降低的问题,本文提出了一种双向流量控制机制BFC,它根据数据链路的双向通信状况, 在前后向两个信道进行流量控制.在前向信道,我们设计了一种显式的ACK详细指示方法,协调多层控制机制及时调节流量;在后向信道,提出了一个ACK流量控制算法,根据双向拥塞状况,对ACK流进行自适应地控制.实验表明,该机制可以有效地提高异构网络传输性能,尤其是当双向信道的不对称参数较高的情况下,该方法显示出独特的优势.

In order to solve the problem that performance of TCP is reduced due to higher bit error rate and bandwidth asymmetry in wireless networks,we put forward a Bi-direction Flow Control mechanism (BFC).It controls traffics in two directions.In the forward channel,according an explicit ACK notification BFC adjusts data rate by cooperating multi-layer protocols.In the reverse one,we developed an ACK flow control algorithm that adjusts self-adaptively ACK rate according to congestion status of two channels.The results of the simulation experiments show that BFC has dramatically improved the performance of TCP over wireless/wired hybrid links.Particularly,in the networks with higher asymmetric factor,BFC has significant contribution.