即时恢复——一种新的TCP拥塞控制快速恢复算法

Instant recovery--a new recovery algorithm for TCP congestion control

针对TCP连接的网络传输中经常会出现同一窗口多个分组丢失的情况,本文提出了一种新的TCP拥塞控制快速恢复算法:即时恢复算法。即时恢复算法能在恢复阶段探测网络的可用带宽,并将之用于窗口拥塞控制。另外,通过动态设定退出恢复阶段的参数域值,除了能恢复首次丢失的多个分组外,该算法还能很好的解决恢复阶段分组进一步丢失的情况。与SACK、FACK TCP等算法需要对TCP协议的发送、接收部分同时修改不同,该算法只需修改协议的发送部分,而接收部分不需作任何改变。在ns仿真环境的仿真结果表明:在同一窗口有多个分组丢失时,即时恢复算法的性能比TCP New-Reno有较大提高,与 SACK TCP性能相当。

To solve the problem that multiple packets were lost from the same window in TCP connections, this paper proposes the instant recovery algorithm, a new TCP congestion control scheme. The functionality of this algorithm is to probe the available bandwidth of the network, which can be used for congestion control. In addition, through dynamically setting the threshold for exiting the recovery period, the instant recovery algorithm can recover the first lost packets and the packets lost later in the recovery period. The implementation of the instant recovery algorithm is easy: contrary to SACK and FACK TCP, the changes of communication software are only required at the sender side; no modifications are needed at the receiver side. The ns simulator is used to evaluate the performance of this algorithm. The simulation results show that the performance of this algorithm is much better than TCP New-Reno, and is not worse than SACK TCP.