摘要： 针对Vegas 拥塞控制技术的不足，提出了一种改进方法。首先对发送分组根据长度进行分类，分别计算各长度类别的“往返时间”(RTT)和RTT 最小值(base_rtt)；在更新发送窗口以及设置重传定时器时，根据分组长度选择属于同一长度范围的RTT 和base_rtt 值作为输入参数。这在一定程度上消除分组长度差异对发送窗口更新和重传定时器设定值所产生的影响，进一步提高协议吞吐率。仿真结果表明，改进的Vegas 能够将原协议的吞吐率提高多达24％。
关键词:
往返时间；TCP Vegas；拥塞控制；重传定时器
Abstract: To overcome the implementing limitation of Vegas, an improved Vegas is proposed. First, it calculates actual RTT and smallest RTT(base_rtt) based on grouping segments by size. While updating congestion window size and setting retransmission timer, the improved Vegas employs the RTT and base_rtt measured for segments belong to the same group. By these step, the improved Vegas can eliminate the negativity of segments size to window size and retransmit timer value in some degree and improve throughput more. Simulating results show that the improved Vegas can improve throughput up to 24% compared to TCP Vegas.
Key words:
Round-trip time; TCP Vegas; Congestion control; Retransmission timer
刘 晶. TCP Vegas 拥塞控制机制的改进[J]. 计算机工程, 2006, 32(12): 130-132.
LIU Jing. Improvement on Congestion Control Mechanism of TCP Vegas[J]. Computer Engineering, 2006, 32(12): 130-132.