On the Design of Overlay Networks for IP Links Fault Verification

Accurate fault detection and location is essential to the efficient and economical operation of ISP networks. In addition, it affects the performance of Internet applications such as VoIP and online gaming. Fault detection algorithms typically depend on spatial correlation to produce a set of fault hypotheses, the size of which increases by the existence of lost and spurious symptoms, and the overlap among network paths. The network administrator is left with the task of accurately locating and verifying these fault scenarios, which is a tedious and time-consuming task. In this paper, we formulate the problem of designing infrastructure overlay networks for verifying the location of IP links faults taking into account the cost of the debugging paths and the stress on the underlying IP links. We map the problem into a integer generalized flow problem, and prove its NP-hardness. We relax the link stress constraint and formulate the resulting problem as a minimum cost circulation that can be solved in polynomial time. We evaluate the fault verification and IP links coverage capabilities of various overlay network sizes and topologies using real-life Internet topologies. Finally, we identify some interesting research problems in this context.