PMTU探测算法分析与研究

Analyzing and Researching on Path MTU Discovery Algorithm

数据包在网络上传输到目标站点,包长不能超过PMTU值。研究PMTU探测算法的目的是为了尽可能封装大的IP数据包,提高网络资源利用率。分析了数据报文分片机制。探讨了目前主流的PMTU探测算法,如递增法,递减法,分层探测算法的优缺点。并在此基础上提出和实现一种改进的PMTU探测算法,经过对不同站点进行测试,结果表明改进的算法发包数量较少,探测值也更精确。

Packets on the network to be transmitted to the target site, the packet length can not exceed the value of PMTU. Study of the Path MTU Discovery Method is designed to encapsulate large IP packet to improve network resource utilization. The mechanic of datagram fragmentation is analyzed. The current main PMTU discovery algorithms, such as increase algorithm, decrease algorithm, and hierarchical algorithm are researched. Based on the above algorithms an improved PMTU discovery algorithm has been proposed and implemented. After testing on various sites, the result indicates that the improved algorithm reduces the number of packets to be send and the detect PMTU value is more accurate.