Generalized Multiprotocol Label Switching (GMPLS), also known as Multiprotocol Lambda Switching, is a technology that enhances Multiprotocol Label Switching (MPLS) to support more advanced network switching for time, wavelength, and space switching as well as for packet switching.

In the GMPLS scenario, every network element has a control plane, known as the C-plane, and the data plane, known as the D-plane. The optical path here is set to exchange protocol messages between various adjacent network elements. The control plane possesses a protocol controller, which is in charge of the following:

• RSVP-TE, which is a signaling protocol that reserves resources, such as for IP unicast and multicast flows, and requests Quality of Service (QoS) parameters for applications
• Open Shortest Path First Traffic Engineering (OSPF-TE) which is used to send out LSAs that have special extensions for traffic engineering
• LMP, which is used for neighbor discovery and link/resource discovery

The database in the GMPLS is used for storing the path/link details and policies.

The GMPLS suite was modified to operate with Synchronous Optical Networks, synchronous digital hierarchy, optical transport network, and wavelength division multiplexing.