A Study of Internet Routing Stability Using Link Weight

The global Internet routing infrastructure is a large scale distributed system where routing changes occur all the time. While prior work on Internet routing dynamics examined routing stability to individual destinations, in this paper we study the routing stability of the Internet as a whole. We use the observed changes in the number of routes over each AS-AS link as a metric and measure such changes from multiple vantage points over a period of one year. We then apply Principal Component Analysis to identify those AS links that were most involved in routing changes. Our work is the first to combine measurement data collected from multiple monitors to gauge the overall routing stability in the Internet. Our results show that very few routing events impact the entire Internet, and those events were due to announcement of new prefixes either in the form of route leakages or address space de-aggregation. We also find that the impact of most routing events is confined to a small scope, and the existence of unstable AS links over long periods of time. We believe our approach represents a new direction in routing stability measurement and our findings shed new insight into the routing system performance.