In a multidomain network, topology aggregation (TA) may be adopted to provide limited information regarding intradomain connectivity without revealing detailed topology information. If the TA information does not include details on the mapping of aggregated links in the TA over the physical topology, then physical disjointness cannot be guaranteed in the case in which two interdomain paths traverse the same domain through different aggregated links. Thus, in order to provide survivability over multiple domains, it may be necessary to find two domain-disjoint paths in the multidomain network. In this paper, we propose an algorithm for finding domain-disjoint working and backup paths for a multidomain connection request. The algorithm modifies the original multidomain network topology by adding cyclic structures that enable the direct application of Bhandari’s algorithm to find a pair of diverse paths with minimum total cost over the modified topology. We give detailed analysis of various scenarios that may occur during the routing procedure, and the corresponding performance of our approach in these scenarios. We show that our approach can achieve good performance in finding domain-disjoint paths with minimum total cost.
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