Border Gateway Protocol Complexity and Stability

In recent years the Internet has grown to a very large and complex system. Covering all continents and an ever increasing number of users, the Internet consists of many important subjects to study. One such subject is the Border Gateway Protocol which assists in routing traffic from one source in the network to another destination in the network. However, previous studies have not focused on how small changes in the network could affect the global behaviour of the network. With a simulator running on a super-computer, real-world scenarios could be investigated. Scenarios are, for example, disconnecting links between Tier 1 Autonomous Systems (AS) and disconnecting a Tier 1 AS completely. Results include the average number of received update messages over all the ASes in a specific Tier, Path Diversity of ASes and Area of Impact. The number of received updates increases if more links are disconnected. Tier 1 ASes receive most of the withdrawals and convert those into announcements. These announcements are in turn received by both Tier 2 and 3 ASes. Path Diversity and Area of Impact might be indicators for the network’s stability. ASes with a high Path Diversity are able to replace withdrawn routes with alternative paths. A small Area of Impact means the failure is local and the network remains stable. In this study sources of instability and complexity are given. However, since many potential parameters were discovered, future study would be necessary to investigate those parameters into more detail.