Introduction to MPlS and GMPLS
(continued)

The Birth of GMPLS

The MPLS researchers proved that a label could map to a color in a spectrum and that MPLS packets could be linked directly to an optical network.  They called this process MPlS or MPLamdaS (Figure 5).   As research continued, it was found that in order to have a truly dynamic network, a method for totally controlling a network within the optical core would be required.  Thus, the concept of intelligent optical networking was born.

Figure 5  MPlS

Since MPLS offered network switching and provisioning could be accomplished automatically in MPLS, this feature could be carried on to the telecom networks and switches could be provisioned using MPLS switch as a core. However, since MPLS was specific to IP networks, the protocols would have to be modified in order to talk to the telecom network equipment.  The generalizing of the MPLS protocol led to the birth of GMPLS – Generalized Multi-Protocol Label Switching.  The protocol suite previously called MPLamdaS became the grandfather so to speak of GMPLS.

In Figure 6, we see a GMPLS network with IP protocol running end-to-end, MPLS protocol running from edge-router to edge-router, and GMPLS running in the middle of the network. Accomplishing the task of controlling the core networks is no simple feat.  It requires the development of different interfaces and protocols. In fact, GMPLS is not just one protocol, but a collection of several different standards written by different standards bodies in order to accomplish a single goal.

Figure 6

Adding a bit more detail to the drawing, we find that the ATM interface is called UNI (User Network Interface), the SONET interface is called O-UNI (Optical User Network Interface), and the DWDM interface can be called LMP (Link Management Protocol)  (Figure 7).

Figure 7  Network with Interfaces Added

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