Calculating a maximally node and SRLG-disjoint path pair of min-sum cost in GMPLS networks

In end-to-end connections it is sometimes not possible to find a totally disjoint path pair. In this context it may be reasonable to accept a path pair which is as disjoint as possible, and thus provide the best (in a certain sense) level of the single fault protection that can be ensured. A Shared Risk Link Group (SRLG) is a group of links which have a common risk of failure (which may result from the sharing of common resources at a lower layer). The concept of SRLG allows an upper layer to be capable of implementing diverse routing, taking into account the existence of common risks of failure. Two heuristics for solving the min-sum maximally node and SRLG-disjoint path pair, formulated as a multi-objective optimization problem, are presented. The relative performance of the heuristics is evaluated using three different networks. The envisaged application scenario of these path calculation algorithms is Generalized Multiprotocol Label Switching (GMPLS) networks.