GMPLS provides broader control over transport networks by supporting multiple switching granularities. Which of the following describes this capability?

• A. It replaces IP routing with a fixed path
• B. It disables optical layer switching
• C. It extends MPLS to support time, wavelength, and spatial switching for broader control
• D. It is identical to standard MPLS with no extra capabilities

Answer: (C)

GMPLS expands MPLS by letting the network control not just packet forwarding but also different switching forms across the transport layer. It adds the ability to set up paths based on time (timeslot switching), wavelength (WDM optical switching), and spatial (path or fiber-level) switching, giving a unified control plane for diverse networks. This is why extending MPLS to support time, wavelength, and spatial switching provides broader, more flexible control over the entire transport network, from IP routing to optical layer provisioning.

The other options don’t fit because they describe limiting or duplicating standard MPLS behavior rather than extending it. Replacing IP routing with a fixed path would reduce flexibility. Disabling optical layer switching contradicts the purpose of GMPLS, which is to enable control of optical switching. Being identical to standard MPLS would ignore the added capabilities for diverse switching granularities.