Diverse working and protection paths are used in telecommunication networks to increase survivability and availability in case of faults. In selecting these diverse paths, it is important that the two paths do not share any links that share the same risk. This is done by assigning each link to a Shared Risk Link Group (SRLG). In this paper, we extend this concept to nodes and domains. Diverse paths should not pass through nodes that can both fail together, for example, by being located in the same building. Similarly, for a higher level of survivability, diverse paths may not pass through network domains that share the same risk. Domains are defined as subnetworks with common administrative control, technology, or geography. Shared Risk Group is an extension of the SRLG concept that avoids not only link level risks but also node and domain level risks. We demonstrate how to use the transport network diversity using this concept while computing application level diversity in a multi-layered optical network.
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