Published on Jun 05, 2023
Generalized MPLS (GMPLS) differs from traditional MPLS in that it supports multiple types of switching, i.e. the addition of support for TDM, lambda, and fiber (port) switching. The support for the additional types of switching has driven GMPLS to extend certain base functions of traditional MPLS and, in some cases, to add functionality.
These changes and additions impact basic LSP properties, how labels are requested and communicated, the unidirectional nature of LSPs, how errors are propagated, and information provided for synchronizing the ingress and egress LSRs.
1. Packet Switch Capable (PSC) interfaces:
Interfaces that recognize packet boundaries and can forward data based on the content of the packet header. Examples include interfaces on routers that forward data based on the content of the IP header and interfaces on routers that forward data based on the content of the MPLS "shim" header.
2 . Time-Division Multiplex Capable (TDM) interfaces:
Interfaces that forward data based on the data's time slot in a repeating cycle. An example of such an interface is that of a SDH/SONET Cross-Connect (XC), Terminal Multiplexer (TM), or Add-Drop Multiplexer (ADM).
3 . Lambda Switch Capable (LSC) interfaces:
Interfaces that forward data based on the wavelength on which the data is received. An example of such an interface is that of a Photonic Cross-Connect (PXC) or Optical Cross-Connect (OXC) that can operate at the level of an individual wavelength. Additional examples include PXC interfaces that can operate at the level of a group of wavelengths, i.e. a waveband.
4. Fiber-Switch Capable (FSC) interfaces:
Interfaces that forward data based on a position of the data in the real world physical spaces. An example of such an interface is that of a PXC or OXC that can operate at the level of a single or multiple fibers.
