The method of pre-configuring the optical protect paths in an agile
photonic network establishes a protection trail for each optical working
path that may be set-up in the network. The pre-configuration is based on
building an electrical layer (EXC) graph that takes into account all the
connection demands in the network, and finding on this EXC graph a
plurality of cycles. Next, the EXC cycles are validated at the optical
layer, and are further validated against constraints. The method attempts
to find an optimal cycles solution, without exhausting all possible
variants.