Question 1
Three PE routers form a point-to-point OSPF area 0 over an Ethernet transport. Observed: The adjacency stays in ExStart after a router replacement with a different interface MTU. Which change most directly corrects the failure while respecting the existing service boundary?
Explanation
Correct Answer
The observed condition is The adjacency stays in ExStart after a router replacement with a different interface MTU. That indicates a database-description mtu mismatch prevents ospf database synchronization. Applying the proposed remedy directly changes that condition. A concrete completion check is: Neighbors reach Full state and exchange the same database summaries.
Incorrect Answers
This change belongs to a different OSPF issue: The interface stays in 2-Way state although the operator expects a Full relationship. That issue involves link network type and adjacency expectations do not match the actual segment design. The current symptom is The adjacency stays in ExStart after a router replacement with a different interface MTU. It instead requires correct the actual path MTU agreement rather than globally bypassing the MTU check.
The option may be useful when a neighbor goes down directly after changing only the ABR area mode, but that is not the current evidence. Here, the adjacency stays in ExStart after a router replacement with a different interface MTU, indicating a database-description mtu mismatch prevents ospf database synchronization. The targeted action is Correct the actual path MTU agreement rather than globally bypassing the MTU check.
This remediates interface ospf priority and the non-preemptive dr election were misinterpreted, normally indicated by A new low-priority device unexpectedly becomes designated router during a maintenance election. It would leave the observed problem (The adjacency stays in ExStart after a router replacement with a different interface MTU) unresolved. Address it with correct the actual path MTU agreement rather than globally bypassing the MTU check.