Refer to the exhibit. This smart city has decided to deploy a converged network for video surveillance and applications for utility services. These new applications are delay-sensitive and require…

RSTP (802.1w) improves on STP but still has convergence times in the range of 1-6 seconds, far exceeding the 50ms requirement.

Ethernet Ring Protection Switching (ERPS), defined by ITU-T G.8032, is specifically designed for Ethernet ring topologies and achieves convergence times of less than 50 milliseconds by using a ring protection link (RPL) mechanism that quickly restores traffic upon failure. It scales to support large rings with many intermediate nodes, making it the correct choice for a smart city ring network requiring strict sub-50ms convergence for delay-sensitive video surveillance and utility applications.

Ethernet Linear Protection (ITU-T G.8031) is designed for point-to-point linear topologies such as SONET/SDH-like paths, not for ring topologies as described in this scenario.

STP (IEEE 802.1D) has convergence times of 30-50 seconds due to its timer-based topology change process, making it completely unsuitable for sub-50ms requirements.