Towards an Aggregation-Aware Internet Routing

Abstract

Internet is composed of a large amount of autonomous systems (ASes). Border Gateway Protocol (BGP) is the de facto standard used to connect these ASes and exchange reachability information between them. The global BGP routing table size in default free zone (DFZ) grows fast due to many factors including IP address allocation, multihoming, and traffic engineering, etc. Increasing prefix fragments consume more memory space and computational capacity in network forwarding devices. It has been known that the Internet has a potential routing scalability issue along with large address space (e.g., IPv6) deployment in the future. Route aggregation is a practical approach to reduce route entries. In this paper, we propose an innovation based on BGP, named Aggregation-aware Inter-Domain Routing (AIDR). It takes advantage of the redundant paths to the same destination in the Internet, and takes route aggregation into account in route selection to get more aggregation for forwarding table (FIB). We give a detailed analysis and evaluation on the effect of AIDR using the public BGP traces from RouteViews and RIPE. It shows that AIDR can produce aggregated FIBs of size roughly 20%~36% of the original routing table size with allowing 2.0 AS path stretch, and 25%~40% without AS path tretch.