Tweak-it: BGP-based interdomain traffic engineering for transit ASs

Abstract

Today, engineering interdomain traffic in large transit ASs is a difficult task due the opacity of BGP and the interactions between the BGP decision process and IGP routing. In this paper we propose Tweak-it, a tool that, based on the steady-state view of BGP routing inside the AS and the traffic demands of the AS, computes the BGP updates to be sent to the ingress routers of a transit AS to traffic engineer its interdomain traffic over time. Tweak-it is based on two components: 1) a scalable BGP simulator (CBGP) that computes the steady-state behavior of BGP routing and 2) a multiple-objectives evolutionary heuristic that can deal with multiple conflicting objectives as they can occur in real networks. Tweak-it takes the intradomain configuration (IGP weights and topology), BGP messages received from peers, BGP routing policies, and traffic demands. By keeping the state of the routing inside the AS up-to-date and based on the traffic demands, the heuristics computes how to engineer the traffic of the AS while trying to minimize the number of BGP tweakings required.