【摘要】 传统的TCP协议,假设丢包都是由网络拥塞造成的,这不适用于错误丢包比拥塞丢包更容易发生的无线链路,而且现有的很多改进方案无法用于加密通讯中.在分析现有改进算法的基础上,提出一种适用于有线/无线混合网络IPSec兼容的端到端的优化机制.通过接收端数据包到达时间间隔的变化累积来判断无线链路的状况,用ACK标记ELN通知发送端,避免不必要的拥塞控制而导致性能下降.通过NS2仿真实验表明该机制能有效提高TCP传输性能还与现有的安全机制兼容.更多还原

【Abstract】 TCP is originally designed only for wired network and assumes that any loss is due to congestion.However,it is different in wireless situation in that wireless errors are more likely to occur than congestion.At the same time,many exist approach can not work when the encryption is used in the communication.This paper proposed a new end-to-end TCP performance improving mechanism,by using the interval movement cumulated of the packets received time on receiver,that can estimate the wireless link condition.Then it marks the ELN(Explicit loss notification)bit to notify the sender and TCP could be modified so as to refrain from going into congestion avoidance.Comparing the TCP Reno and the modified TCP,by simulations using NS2,the results show it achieves an great improvement over wired-cum-wireless networks and can work together with current security mechanism.更多还原