Backup routing for BGP: Virtual ring routing scheme

Despite of the high connectivity of the Internet, border gateway protocol (BGP) often loses connectivity in the case of no alternate routes to destination. To ensure that Internet domains stay connected, this paper employs virtual ring routing scheme to provide a backup routing path for BGP. We evaluate the performance of virtual ring routing scheme by simulations on a BGP-connected topology with autonomous system (AS) relationship. Considering AS relationship and routing policy, we compare the effectiveness of virtual ring routing scheme under two situations on no-policy topology and policy topology. Routing policy does not impact virtual ring routing scheme greatly. More importantly, although virtual neighbor paths are compatible with the routing policy of ldquovalley-freerdquo, there are a number of routes on the virtual ring to violate this policy. How to deal with this problem is a key to implement virtual ring routing scheme for BGP. Assignment of AS identifier according to AS relationship is a promising way to get valid backup routes. In addition, the result of experiment shows high degree ASes provide much more routing information and undertake main task of transferring on the virtual ring. Anyway, this paper takes an initial work on virtual ring routing scheme as a backup routing for BGP considering AS relationship and routing policy.