BGP-based interdomain traffic engineering

by Quoitin, Bruno

In a few years, the Internet has quickly evolved from a research network connecting a handful of users to the largest distributed system ever built. The Internet connects more than 20,000 Autonomous Systems (ASs) which are administratively independent networks. While the initial Internet was designed to provide a best-effort connectivity among these ASs, there is nowadays a growing trend to deploy new services such as Voice/Video over IP or VPNs. To support these emergent services, ASs need to better engineer their Internet traffic. Traffic Engineering encompasses several goals such as better spreading the traffic load inside a network and obtaining better end-to-end performance (lower latency or higher bandwidth).

Engineering the traffic inside a single AS is feasible and pretty well understood. To the opposite, interdomain traffic engineering is still a difficult problem. The main issue comes from the current Internet routing architecture, articulated around the Border Gateway Protocol (BGP). BGP propagates a subset of the Internet topology for scalability and stability reasons and does not optimize a single global objective. This limits the control each AS has on its routing and has dramatic implications for interdomain traffic engineering.

In this thesis, we evaluate the primitive BGP-based routing control mechanisms. For this purpose, we designed and implemented a new approach for modeling BGP on large Internet-scale network topologies. Finally, to overcome the limitations of BGP in terms of routing control, we propose Virtual Peerings, a new mechanism based on a combination of BGP and IP tunneling. We apply Virtual Peerings to solve various interdomain traffic engineering problems such as balancing the load of Internet traffic received by an AS or decreasing the end-to-end latency of Internet paths.