摘要： 分析了传输控制协议（Ｔｒａｎｓｐｏｒｔ　Ｃｏｎｔｒｏｌ　Ｐｒｏｔｏｃｏｌ，ＴＣＰ）的４个交互的拥塞控制算法：慢启动、拥塞避免、快速重发送和快速恢复。重点研究了慢启动和拥塞避免的具体算法，给出了Ｃ＋＋语言实现的程序。另外，讨论了在相当长的闲置时间后，ＴＣＰ如何传输的问题以及各种不同的产生确认（ＡＣＫＳ）的方法，最后探讨了ＴＣＰ丢失数据包窗口的恢复和网络安全问题。

关键词: 拥塞控制, 传输控制协议, 确认, 算法

Abstract: This paper discusses TCP's four interwined congestion control algorithms, namely， slow start，congestion avoidance, fast retransmit and fast recovery. The mechanism how TCP should begin transmission after a relatively long idle period is analysed. A number of acknowlegment generation methods are developed with an emphasis on congestion avoidance. An algorithm and a piece of C++ code are finally given to implement the proposed congestion avoidance approaches.

中图分类号: 

• TP393.04