Question 100
What adverse result should the acceptance board consider most important in this case: A high-speed optical link shows intermittent FEC corrections rising under rack vibration despite no link-down alarms?
Explanation
Correct Answer
Without correction, Treating link-up as proof of signal quality can leave training jobs exposed to sporadic packet faults. The relevant engineering principle is that Corrected FEC events can reveal deteriorating signal margin before hard link failures occur, rather than unrelated network or GPU behavior.
Incorrect Answers
The option would apply to “An installation map labels AOC and DAC assemblies interchangeably and technicians order the wrong reach for distant racks”. The acceptance board should flag that Incorrect media selection can cause link failures and repeated expensive cable replacement. This question instead requires “Treating link-up as proof of signal quality can leave training jobs exposed to sporadic packet faults”.
The related but distinct situation is “An engineer installs an optic that matches the physical cage but uses a wavelength incompatible with the remote transceiver”. The acceptance board should flag that Wrong optical modules can fail training traffic intermittently or never establish a usable link. For the stated problem, “Treating link-up as proof of signal quality can leave training jobs exposed to sporadic packet faults” addresses the central condition.
This alternative addresses the separate case “A 400G fabric port uses a short passive copper cable beyond its approved reach and link quality is unstable”. Without correction, Exceeding cable reach can create intermittent bit errors despite occasional link-up status. The deciding requirement here is “Treating link-up as proof of signal quality can leave training jobs exposed to sporadic packet faults”.