  p-Cycles offer ring-like switching speed and mesh-like spare capacity
efficiency for protecting network against link failures. This makes them
extremely efficient and effective protection technique. p-Cycles can also
protect all the links in a network against simultaneous failures of multiple
links. But it has been mostly studied for single link failure scenarios in the
networks with the objective to minimize spare capacity under the condition
of100% restorability. For large networks, use of p-cycles is difficult because
their optimization requires an excessive amount of time as the number of
variables in the corresponding Integer Linear Program (ILP) increase with the
increase in the network size. In a real-time network situation,setting up a
highly efficient protection in a short time is essential.Thus, we introduce a
network sub-graphing approach, in which a network is segmented into smaller
parts based on certain network attributes. Then, an optimal solution is found
for each sub-graph. Finally, the solutions for all the sub-graphs is combined
to get a sub-optimal solution for the whole network. We achieved better
computational efficiency at the expense of marginal spare capacity increases
with this approach.
