Informed dynamic shared path protection

Summary form only given. A generalized optical network consists of multiple optical cross-connects (OXC) that are interconnected via bi-directional WDM links in a general topology, often referred to as intelligent optical mesh network. A major aspect of this intelligence is the ability to provide fast provisioning and restoration. To achieve this, there is a need for a unified control plane responsible for running routing and traffic engineering protocols, achieved, for example, through the introduction of GMPLS. The control plane queries and modifies the wavelength-switching table of the cross-connect; floods the reservation tables of the cross-connect (through OSPF or IS-IS) in the network; is responsible for connection setup/tear-down through CR-LDP (or RSVP-TE). A mesh-restored lightpath in an optical network is allocated a pair of link-disjoint paths, where one of the path is the primary or working path and the other is backup or protection path that is activated only in case of failure. Each link in the primary path has dedicated capacity allocated to a connection. The protection path can also have dedicated capacity (1 + 1 restored lightpath), however that results in inefficient use of network capacity. In contrast, in shared or 1:N restored lightpath, the protection capacity is shared with the backup path for other restored connections, hence resulting in improved utilization of the network resources. The efficiency of distributed 1:N mesh restoration can be enhanced substantially by providing information about the protection topology. This information can be disseminated using extensions to OSPF. In order to keep the bandwidth of the distributed information low, only recent modifications in the protection tables need be distributed. Calculations indicate substantial savings (up to 35%) in terms of protection wavelength mileage due to much better sharing of backup resources. In addition, the scheme allows for different algorithms when choosing paths that share a link, thus potentially enabling protection in case of multiple failures.