Gunnar Bornemann

ii Routing packets between autonomous systems (ASes) is a very important part of the Internet. As large networks with many connections to neighbors can become quite complex, it is impossible for an administrator to verify that routing is operating correctly by looking into the routers manually. Therefore a more automatic way of monitoring routing information, which is commonly exchanged through the Border Gateway Protocol (BGP), is needed. Therefore we analyze BGP routing information collected from various points in our network and the Internet. The analysis is needed to gain knowledge on what infor-mation can be abstracted from the BGP data and how this information will help us with detecting abnormal behavior in our routing. We also design a system that automatically collects and analyzes such routing information. It logs abstracted in-formation and reacts to detection of such abnormal behavior with sending alarms via e-mail. The design is then also implemented and tested in our AS