A multi-layer restoration strategy for reconfigurable networks

The multi-layer restoration strategy (MRS) is an integrated solution for link, path and node failure restoration in SDH/SONET networks. Extension to circuit assignment is also straightforward. MRS consists of two parallel processes; for both pre-planned and real-time restoration. The pre-planned restoration process attempts to make connections along a preferred path to achieve extremely fast, low-contention, pre-optimised restoration. The real-time restoration process supplements this to ensure high restorability when the preferred route does not succeed in establishing a connection. By employing a distributed background route finder, MRS also offers both a means of network restorability assessment and distributed route optimisation.