重传TCP确认包及在长期演进网络中的应用

Retransmitting TCP acknowledgement packet and its application in long term evolution network

为避免传输控制协议(TCP)机制因确认包丢失而引起的不必要的数据包重传,提出通过增加确认包重传定时器来重传丢失的确认包,利用较小的初始重传时间和固定的重传间隔使接收端的确认包重传比发送端的数据包重传发生的更早.为验证重传确认包机制的有效性,用网络仿真工具NS 2构建了一个长期演进网络模型.基于此模型的仿真结果表明,系统的性能得到了显著的提高:在150个有效用户下,平均延迟下降了16%,平均抖动下降了14%,平均丢包率下降了10%,总吞吐量上升了17%.

To avoid unnecessary data packet retransmission caused by the lost of the acknowledgement packet in the transmission control protocol（TCP） mechanism,a retransmission timeout（RTO） timer was added to retransmit the lost acknowledgement packet.The small initial RTO value and the fixed RTO duration were used to make sure that the RTO timer of the acknowledgement packet in the receiver expired earlier than that of the data packet in the sender.To verify the mechanism of the acknowledgement packet retransmission,a long term evolution network model was built with network simulation tool NS 2.Simulation showed that the system performance was improved significantly： average delay decreased by 16%,average jitter decreased by 14%,average packet loss rate decreased by 10%,and total throughput increased by 17% with 150 active users.