Question 260
During a planned campus-network change at a public library in Portland, operators discover that a new bridge with a superior bridge ID displaces the planned distribution-layer STP root. The design must preserve staff and visitor wireless access. Which post-change observation is the strongest acceptance evidence?
Explanation
Correct Answer
This observation tests the RSTP root election and loop prevention requirement at a public library in Portland. The expected result is that expected root and blocked/forwarding port roles appear without persistent topology flaps or broadcast storms. The necessary correction is to designate the intended spanning-tree root and validate port roles, priorities and topology-change information before enabling alternate links; a saved configuration alone would not prove it is working. In this case, the observed fault is that a new bridge with a superior bridge ID displaces the planned distribution-layer STP root.
Incorrect Answers
At a public library in Portland, the observation may be useful for a separate DHCP snooping and rogue DHCP protection test, but it does not establish that a new bridge with a superior bridge ID displaces the planned distribution-layer STP root has been resolved. The relevant check is the RSTP root election and loop prevention outcome.
At a public library in Portland, this would verify Layer-two edge protection and BPDU controls, not the failure reported in this scenario. The requested closure criterion instead concerns RSTP root election and loop prevention: expected root and blocked/forwarding port roles appear without persistent topology flaps or broadcast storms.
At a public library in Portland, the observation may be useful for a separate Ingress ACL enforcement and least privilege test, but it does not establish that a new bridge with a superior bridge ID displaces the planned distribution-layer STP root has been resolved. The relevant check is the RSTP root election and loop prevention outcome.