<p>A method supports incremental deployment of maximally redundant trees-fast reroute (MRT-FRR) by supporting MRT-FRR within an island of nodes in the network. A destination node and next hop failure selected to calculate detour paths. The clean set of nodes is calculated. The clean set of nodes is expanded with extended island candidate nodes that are reachable by a border node within the island via shortest path first (SPF) to the destination node that does not pass through the failed next hop. The extended island candidate nodes that are reachable by the border node within the island via SPF are part of an extended island. An MRT is calculated for each extended island candidate node. A candidate node is selected from the clean set of nodes according to a configured optimization option to serve as the endpoint of detour path to a destination node.</p>
