Internet Flattening: Monitoring and Analysis of Inter-Domain Routing

The decrease of AS-level route length, called Internet flattening, has a significance impact on the the design of next generation global routing system. However, there is little quantitative assessment of its factors. We report our findings through monitoring and analysis of inter-domain routing. Using BGP routing table and update messages from RouteViews and RIPE RIS, we explore Internet flattening from a view of global inter-domain routing system. Our study shows that Internet flattening is from two dominating sources: (1) ASes close to Tier 1 contribute 36% of the total decrease in route length; and (2) Routes bypassing Tier 1 is responsible for 53% of the total decrease in route length. Our measurement results also indicate that multi-homing is not an important reason of Internet flattening. Besides, leading Content Providers contribute to Internet flattening ten times than that by Internet Service Providers. Base on our result, we propose mechanisms for the performance improvement for Content Providers.