SDN Candidate Selection in Hybrid IP/SDN Networks for Single Link Failure Protection

We focus on the problem of selecting a smallest subset of IP routers for upgrading to SDN switches to protect all single link failures in a given network, or the SDN candidate selection problem. In solving the problem, we also aim at minimizing the repair path length for reducing the delay experienced by the rerouted traffic and saving network bandwidth. The key enabler is a novel tunneling mechanism for constructing multi-tunnel repair paths by leveraging multiple SDN switches. Multi-tunnel repair paths provide additional flexibility in rerouting and a new SDN candidate selection (SCS) algorithm is then designed to take advantage of them. To further reduce the repair path length, we propose to replace the link-based tunneling adopted by fault-detection routers by destination-based tunneling. If the network traffic distribution is available, we further show that destination-based tunneling can be used to avoid network congestion.