Availability Guaranteed Service Provisioning in Hose Model VPNs with Multi-Path Routing

In this paper we investigate the problem of availability guaranteed service provisioning in hose model VPNs. We show that this problem is NP-complete and propose a multi-path routing heuristic to solve it. The heuristic finds multiple link-disjoint paths for each VPN endpoint pair, thus enabling alternative paths to raise the overall availability. This approach elegantly solves the too-many-path problem encountered by others in literature and eliminates the associated complexities. It makes the provisioning of availability guaranteed connections fast and straightforward. Simulation results show that the proposed heuristic significantly increases the overall availability for each possible VPN endpoint pair. Compared with tree routing scheme, the blocking probability of the new scheme is reduced by a few orders of magnitude. This is highly significant.