一种拥塞感知的TFRC协议慢启动算法  

A Congestion Aware Slow-Start Algorithm for TFRC Protocol

作　　者：蒋翊[1] 吴春明[1] 姜明[2] 

机构地区：[1]浙江大学人工智能研究所,浙江杭州310027 [2]杭州电子科技大学计算机学院,浙江杭州310018

出　　处：《电子学报》2009年第5期1025-1029,共5页Acta Electronica Sinica

基　　金：国家自然科学基金(No.60773182);国家“863”重大项目课题(No.2008AA01A323);浙江省科技计划项目(No.2007C21031)

摘　　要：本文分析了TFRC(TCP-Friendly Rate Control)协议在慢启动阶段采用类似TCP协议的倍增发送速率机制存在的问题,提出了一种利用回路响应时间(Round Trip Time,RTT)来自适应调节慢启动阶段速率的算法.通过分析实际RTT值和EWMA(Exponentially Weighted Moving Average)处理后的平均RTT值来感知网络当前的拥塞状况,以调节发送速率的激进程度.仿真实验表明,该方法对TFRC协议具有明显的改进作用,减少了慢启动阶段结束时的报文丢失率,提高了协议的传输平稳度和吞吐量,从而能更有效地适应多媒体流的传输要求.This paper analyzes the problem of TFRC （TCP-Friendly Rate Control） protocol in slow-start phase in which the sending rate increases exponentially like that in the TCP protocol,and proposes a method of using round trip lime （RTr） to adjust the sending rate adaptively in this phase. The method can detect the network congestion degree by comparing the sample RTI＂ with the average RTr and then adjust the aggressiveness of sending rate in slow-start phase. The simulation results indicate that with this method, TFRC reduces the packet loss rate before entering the congestion avoid phrase,and improves the throughput and smoothness property, thus meeting the requirements of multimedia stream more effectively.

关 键 词：TFRC协议 慢启动 拥塞感知 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]