What does GMPLS extend MPLS to support?

• A. Time and frequency hopping
• B. Dynamic routing protocols
• C. Time, wavelength, and spatial switching
• D. Only wavelength switching

Answer: (C)

GMPLS generalizes MPLS to handle switching beyond packets, allowing the control plane to manage resources across time, wavelength, and the physical path. Time switching covers time-slot or TDM-style resources, wavelength switching covers the use of different light wavelengths in WDM networks, and spatial switching covers different fibers or cross-connect paths. This broader capability lets network controllers provision and steer diverse optical resources automatically, which is exactly what GMPLS is designed to do.

The other options don’t fit as well. Time and frequency hopping isn’t the focus here, since GMPLS is about coordinating switching resources rather than wireless timing or frequency techniques. Dynamic routing protocols are already part of MPLS/GMPLS, and stating that doesn’t capture the expansion to new resource types. Limiting to only wavelength switching misses the essential addition of time and spatial switching that GMPLS brings to the table.