网络非对称链路带宽的测量

研究了数据分组在IP网络中传输时RTT时延的组成，给出了RTT时延与分组长度的线性表达式。分析了传统利用UDP测量分组RTT时延与测量分组长度的线性关系进行链路带宽测量的算法，针对该测量算法不能对非对称链路带宽进行测量的缺陷，提出了一种新的非对称链路带宽测量算法Asy_pathchar。同时使UDP报文和ICMP报文作为测量报文，Asy_pathchar能够对测量分组所经过的每一跳非对称链路的带宽进行测量，实验结果验证了算法的正确性。
关 键 词 链路带宽; 带宽测量; 非对称链路; RTT时延

Abstract By studying the construction of the RTT latency, alinear expression between the RTT latency and the packet size is presented. Then pathchar,traditional bandwidth measurement algorithm,based on the relationship between the RTT latency and the packet size, is analyzed particularly. But pathchar can not measure the asymmetric link bandwidth. To solve this problem, Asy_pathchar, a new algorithm, is put forward, which can measure each hop’s link bandwidth in both directions in an IP network using the UDP packet and ICMP packet.Finally an experiment is given to validate the new algorithm.
Key words link bandwidth; bandwidth measurement; asymmetric link; RTT latency