Techniques for Determining the Geographic Location of IP Addresses in ISP Topology Measurement

A brief survey on the state-of-the-art research of determining geographic location of IP addresses is presented.The problem of determining the geographic location of routers in Internet Service Provider (ISP) topology measurement is discussed when there is inadequate information such as domain names that could be used. Nine empirical inference rules are provided, and they are respectively (1) rule of mutual inference, (2) rule of locality, (3) rule of ping-pong assignment,(4) rule of bounding from both sides, (5) rule of preferential exit deny, (6) rule of unreachable/timeout, (7) rule of relay hop assignment, (8) rule of following majority, and (9) rule of validity checking based on interface-finding. In totally 2,563discovered router interfaces of a national ISP topology, only 6.4% of them can be located by their corresponding domain names. In contrast, after exercising these nine empirical inference rules, 38% of them have been located. Two methods have mainly been employed to evaluate the effectiveness of these inference rules. One is to compare the measured topology graph with the graph published by the corresponding ISP. The other is to contact the administrator of the corresponding ISP for the verification of IP address locations of some key routers. The conformity between the locations inferred by the rules and those determined by domain names as well as those determined by whois information is also examined. Experimental results show that these empirical inference rules play an important role in determining the geographic location of routers in ISP topology measurement.