What are the main problems faced by the traditional subway MTSP embedded RPR solution? (Multiple Choice)

Question

Options

• AARPR supports a maximum bandwidth of 1.25G per ring, and large bandwidth requirements are
• BUnable to communicate across rings and limited networking
• CDoes not support cross-board and cross-device protection

• A
  100% (35)

Explanation

All three options identify genuine limitations of the traditional subway MTSP embedded RPR architecture, which is why A, B, and C are all correct. Since every listed choice is a valid problem, there are no distractors to rule out in this question - a useful signal that the exam is testing comprehensive recall of the technology's weaknesses.

A is correct because RPR rings using ARPR top out at 1.25 Gbps per ring, making the solution inadequate for modern high-bandwidth subway communication needs (video surveillance, passenger Wi-Fi, operational data combined). B is correct because RPR is inherently a single-ring protocol; nodes on different rings cannot natively route traffic to each other, creating isolated network islands that limit scalability in a multi-ring subway topology. C is correct because the embedded RPR design lacks protection mechanisms that span multiple boards or physical devices, meaning a fault in one chassis can disrupt service without an adequate failover path.

Memory tip: Think of "3 walls" - RPR hits a bandwidth wall (1.25G max), a ring wall (can't cross rings), and a device wall (no cross-device protection). If a technology can't scale up, across, or through, it fails in a modern metro network.

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