基于排队时延和丢包率的拥塞控制

作为拥塞度量，排队时延具有很多优点，但仅利用排队时延并不能完全避免丢包，而在链路缓存不足出现丢包时，排队时延已不能有效反应网络拥塞情况。该文提出了一种基于排队时延和丢包率的拥塞控制模型，该模型采用双模控制的方法。在瓶颈链路上有足够缓存时，模型利用排队时延作为拥塞度量，使各流获得稳定的动态性和成比例公平性。当瓶颈路由器上没有足够缓存不可避免要丢包时，模型利用丢包率作为拥塞度量，使各流仍能获得与不丢包情况下相近的流特性。模型在两种模式的切换中保持稳定，实现平滑过渡。

Congestion Control Based on Queuing Delay and Packet Loss Probability

As a congestion measure, queuing delay has many advantages. But packet loss can not be completely avoided if only queuing delay is used as a congestion measure. When the buffer is not large enough and some packets are dropped, queuing delay can not accurately reflect network congestion. In this paper, a congestion control model is proposed based on queuing delay and packet loss rate, in which dual-mode control is used. When the buffer is large enough, queuing delay is used as a congestion measure, the model achieves stable dynamic properties and weighted proportional fairness among heterogeneous flows. When the buffer is not large enough and packet loss is inevitable, packet loss rate is used as a congestion measure, and the model maintains almost the same performance as when there is no packet loss. The model is stable as it switches between the two modes and the transition is smooth.