US Patent 7324750 Protection scheme for a communication network

Method and apparatus for implementing a protection scheme for switched networks, and particularly GMPLS networks are described. One embodiment is a method of reserving communications channels comprising an alternative path through a switched network, the network comprising a plurality of nodes interconnected by links, wherein each link comprises at least one communications channel. The method comprises simulating failure of a first link; noting a second link over which traffic on the first link is rerouted in the event of failure of the first link; and transmitting a protection request message (“PRM”) from the first link to the second link to request reservation of a specified number of communication channels on the second link.