Survivability provisioning in optical MPLS networks

Advanced WDM technology has generated large-scale interest in the IP-over-WDM paradigm for next-generation optical networks. Current work has essentially focused on defining a new (access) protocol layer for WDM networks (optical-layering approach), providing "circuit-switched'' services to higher-layer protocols. Meanwhile, network survivability has long been a crucial concern, and traditionally SONET/SDH technology has been used to provide high reliability. However, a new optical layer raises some complex interworking concerns, many of which still need further investigation. Conversely, more direct standards-based IP-over-WDM integration approaches, such as lambda-labeling and multiprotocol lambda switching, have also been proposed To reduce layering/complexity. These schemes extend the MPLS framework and use its label-switching concept to provision wavelength-switched lightpaths. MPLS LSP recovery capabilities can naturally subsume many WDM survivability proposals, e.g., end-to-end path and/or sub-path recovery, resource sharing, and even fiber-level protection.