摘要
分析目前TCP拥塞控制的慢启动策略及其存在的短连接带宽浪费、过度丢包等实际问题,提出一种基于RTT(Round-Rrip Time,往返时延)反馈的TCP慢启动改进算法SS-IM(Slow-Start Improved)。改进算法在慢启动过程前期为快速利用当前有效网络带宽,拥塞窗口保持较高速度增长,后期为避免加重网络拥塞,根据当前网络状况动态地缓慢调整拥塞窗口增长因子,使cwnd(congestion window,拥塞窗口)平滑过渡到ssthresh(slow-start threshold,慢启动阈值)。性能分析和NS2仿真实验结果表明,改进算法能有效地减少分组丢包数,提高网络吞吐量,降低路由排队时延,平缓数据突发量冲击,降低网络拥塞发生的可能性,利于网络性能的提高。
The current slow start strategy of TCP congestion control and its existing practical problems like short connection band- width waste, excessive packet loss are analyzed, and a kind of Improved Slow Start algorithm SS-IM（ Slow-Start Improved） is put forward, which is based on RTT（ Round-Rrip Time） feedback. In the early stage of the process of slow start, improved algorithm can quickly use the current effective network bandwidth so as to keep congestion window high speed growth, and in the later stage, to avoid aggravating network Congestion, a dynamic incremental factor is introduced based on the current network status, so as to make the cwnd （ congestion window） smooth transition to the ssthresh （ slow-start threshold）. Performance analysis and NS2 simulation results show that the improved algorithm can effectively reduce packet number of packet loss, improve the network throughput, reduce routing queuing delay, gentle data quantity of sudden impact, reduce the possibility of network congestion, conduce to the improvement of the network performance.
出处
《计算机与现代化》
2015年第12期25-30,共6页
Computer and Modernization
