一种有效的TCP和UDP混合流队列长度控制方法

在分析基于TCP流量控制的随机微分方程(SDE)模型的基础上,针对现有微分流量模型无法描述UDP流量变化的问题,在路由器队列长度变化中引入UDP流量的影响,建立TCP和UDP混合流量的随机微分方程模型,实现了对原有TCP微分流量模型的扩展。通过求解TCP和UDP混合流量稳定状态下的分组丢弃概率,改进了原有基于TCP流的RED队长控制方法,结合RED算法本身来调整其算法的参数,以保持路由器缓存中的队列长度稳定在期望队长附近,有利于控制和保证端到端的延时,使原有的基于TCP流的RED队列长度控制方法能应用于TCP和UDP的混合流。仿真实验表明,改进后的面向TCP和UDP混合流的RED队列长度控制方法对于TCP以及TCP和UDP的混合流均具有较好的适应性,采用该方法可使路由器的实际队列长度保持在期望控制队列长度附近波动。

Efficient Method to Control Queue Length for Mixture Flows of TCP and UDP

Based on the analysis of TCP flow control stochastic differential equation(SDE)model,in view of UDP having no flow control mechanism like congestion control and differential equation which takes window-based control being unable to describe the character of UDP running process,the original TCP flow control stochastic differential equation was modified.By means of adding UDP affections to the changing of router's queue length,a new model was set up to analyze the mixture flows of TCP and UDP.After getting the root of steady state packet's discarding possibility,the original RED queue length control method for TCP flow could be applied to the mixture flows of TCP and UDP.The simulation result shows that the improved method of RED queue length control is fit for not only TCP flows but also the mixture flows of TCP and UDP.With this method,actual router queue length can be kept fluctuating around the vicinity of expected queue length.