Question 180
An IS-IS wide-metric topology has parallel unequal-speed core links. Observed: Both links receive the same metric despite service quality differences. Which ongoing validation gate would best detect a recurrence of this problem?
Explanation
Correct Answer
A useful regression gate tests whether the shortest-path result reflects distinct link costs and operational flow validation and alerts when both links receive the same metric despite service quality differences. This directly checks the technical weakness: Default metrics were left unchanged after the capacity upgrade. The gate is derived from the fictional incident and is not an independent Juniper engineer signoff.
Incorrect Answers
It is valid for another service scenario but checks the device has healthy local adjacencies but does not know any level 2 exit. This case instead needs a gate for both links receive the same metric despite service quality differences and evidence that the shortest-path result reflects distinct link costs and operational flow validation.
The proposed control is tied to import and export policy lack route-origin tagging or other feedback suppression, typically observed when the route repeatedly returns to the protocol it came from. Here the target is default metrics were left unchanged after the capacity upgrade; monitor the shortest-path result reflects distinct link costs and operational flow validation.
This gate monitors a different failure, the loopback is missing from other routers even though link adjacencies are healthy. It would not detect the current problem: Both links receive the same metric despite service quality differences. The appropriate check requires the shortest-path result reflects distinct link costs and operational flow validation.