Cisco
352-001 · Question #448
352-001 Question #448: Real Exam Question with Answer & Explanation
The correct answer is B: Ethernet Ring Protection. Ethernet Ring Protection (ITU-T G.8032) is purpose-built for ring topologies and guarantees convergence under 50 milliseconds.
Question
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 strict convergence times of less than 50 milliseconds. The network is expected to have up to 50 intermediate distribution frames per ring. Which protocol provides less than 50 milliseconds convergence time?
Exhibit
Options
- ARSTP
- BEthernet Ring Protection
- CEthernet Linear Protection
- DSTP
Explanation
Ethernet Ring Protection (ITU-T G.8032) is purpose-built for ring topologies and guarantees convergence under 50 milliseconds.
Common mistakes.
- A. RSTP (802.1w) improves on STP but still has convergence times in the range of 1-6 seconds, far exceeding the 50ms requirement.
- C. 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.
- D. 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.
Concept tested. Ethernet Ring Protection G.8032 sub-50ms convergence
Reference. https://www.itu.int/rec/T-REC-G.8032/en
Community Discussion
No community discussion yet for this question.