Reliable Routings in Networks With Generalized Link Failure Events

We study routing problems in networks that require guaranteed reliability against multiple correlated link failures. We consider two different routing objectives: The first ensures ldquolocal reliability,rdquo i.e., the goal is to route so that each connection in the network is as reliable as possible. The second ensures ldquoglobal reliability,rdquo i.e., the goal is to route so that as few as possible connections are affected by any possible failure. We exhibit a trade-off between the two objectives and resolve their complexity and approximability for several classes of networks. Furthermore, we propose approximation algorithms and heuristics. We perform experiments to evaluate the heuristics against optimal solutions that are obtained using an integer linear programming solver. We also investigate up to what degree the routing trade-offs occur in randomly generated instances.