变结构拥塞控制协议VCP研究

Study on Variable-Structure Congestion Control Protocol

当网络的带宽或者时延增大时,TCP协议的性能严重下降,最显著的就是网络瓶颈处带宽利用率很低。Xia提出的变结构拥塞控制协议(VCP)可有效地解决上述问题。在VCP协议中,每个路由器每隔200毫秒的计算一个“负载因子”以反映网络的拥塞程度,并将其编码放入每个经过数据包的两位ECN位中。源主机根据数据包中的负载因子,执行不同的拥塞控制算法,分别提高带宽利用率和公平性。与其他的显式拥塞控制协议相比,VCP仅使用了很少的(两位)比特数,但是仍获得了较好的性能。

TCP＇s performance degrades significantly as either bandwidth or latency increases. The most noteworthy aspect of this poor performance is the low bandwidth utilization in bottleneck. Variable-structure Congestion control Protocol （VCP） proposed by Xia addresses this problem efficiently. With VCP, each router computes a ‘ load Factor＇, which indicates the level of network congestion, at intervals of 200ms and encodes this information into two ECN bits of each packet through the router. Due to the load factor in the packet, the source host uses different algorithms to improve bandwidth utilization and fairness respectively. Compared with other explicit congestion protocol, VCP used only two bits, but still achieves considerable performance.