New Approach to Reliable Multipath Provisioning

We study the problem of reliably provisioning traffic in high-capacity backbone mesh networks supporting virtual concatenation (VCAT). Traditional approaches handled reliability requirements using full protection, which offers high assurance but can be costly. We take a less expensive approach by offering an expected bandwidth, rather than an absolute amount, but at lower costs than full-protection approaches. We propose a new routing algorithm that uses minimum-cost flow to find efficient collections of paths that satisfy traffic requests for expected bandwidth. We find that in most realistic network settings, paths are reliable enough so that only few additional network resources are required to compensate for the bandwidth loss incurred from possible network failures. We compared our approach to a previous algorithm under both a uniform setting, with symmetric traffic distribution and equal edge capacities, and in a more realistic setting with asymmetric traffic and differing edge capacities. Results show that our algorithm is an attractive approach in both settings, and much more effective than the previous scheme. We also compare our approach to a full-protection approach. Results show that by using fewer network resources, our algorithm is able to satisfy significantly more traffic requests than full protection. Thus, when full protection is not crucial, using our routing approach should be beneficial.