Study Of BGP Routing Policy And Verification Method Between AS

Internet is divided into more than 17000 Autonomous Systems (ASes) that interact to coordinate the delivery of IP traffic. An AS typically falls under the administrative control of a single institution, such as a university, company, or Internet Service Provider (ISP). Border Gateway Protocol allows Autonomous Systems to apply diverse routing for selecting routes and for propagating reachability information to other ASs. The main reasons for the selective announcement are due to traffic engineering strategy for controlling incoming traffic. The impact of these routing policies might be significant and the selective announcement routing policies imply that there are much less available paths in the Internet than shown in the AS connectivity graph. The robustness of the Internet relies heavily on the robustness of BGP routing.We thoroughly investigate the problem of BGP routing policy in Internet and Character the import and export routing policies between ASs. the research works in the BGP routing policies verification field are mostly located in the static analysis of router's configuration files in an AS. Very few works have been done between AS. We thoroughly investigate the route policy between ASs, then present a method that can conduct new policies. On the basis of that, we also present a method of between AS polices verification based on AS relationships. Finally ,we even developed a toolkit of verification routing policy base on AS relationship. Through this method we can find out the abnormal prefix advertise to verify the route policies. We took an experiment for our method between two ASs in AT&T, and the results are good.