A protocol that extends MPLS beyond packet switched interfaces to include Time Division Multiplexing (TDM),Wavelength Division Multiplexing (WDM), and Add/Drop Multiplexing (ADM). GMPLS adds the concept of label switching to photonics at the lambda level in a Wavelength Division Multiplexing (WDM) system, to time slots in a SONET/SDH system, and to physical optical fibers in an optical cross-connect (OXC). GMPLS is designed to speed the provisioning of end-to-end traffic-engineered paths in the TDM and optical domains, much as MPLS has done in the Internet Protocol (IP) domain. GMPLS was known as Multiprotocol Lambda Switching before it was extended to other media. See also ADM, domain, lambda, optical fiber, OXC, packet switch, photonics, physical, PXC, SDH, SONET, TDM, time slot, traffic engineering, wavelength, and WDM.
(Generalized Multiprotocol Label Switching) In a WDM optical networking system, it is the ability to route a data transmission based on the wavelength of light that carries it. The routing device only analyzes wavelengths (light frequencies) to make its forwarding decision rather than inspecting fields within each packet. GMPLS adds numerous enhancements to MPLS in order to support optical networks. Originally known as Multiprotocol Lambda Switching, the "L" in the acronym MPLS was the Greek lambda. See MPLS, lambda and WDM.