A packet network of interconnected nodes employing dynamic backup routing of a
Network Tunnel Path (NTP) allocates an active and backup path to the NTP based
upon detection of a network failure. Dynamic backup routing employs local restoration
to determine the allocation of, and, in operation, to switch between, a primary/active
path and a secondary/backup path. Switching from the active path is based on a
backup path determined with iterative shortest-path computations with link weights
assigned based on the cost of using a link to backup a given link. Costs may be
assigned based on single-link failure or single element (node or link) failure.
Link weights are derived by assigning usage costs to links for inclusion in a backup
path, and minimizing the costs with respect to a predefined criterion.