A Catalyst 9800 pair will not form stateful switchover. The redundancy link is up, and the standby chassis is running a different software release from the active. What has to match?
Select an answer to reveal the explanation.
Short Explanation
The redundancy link is up, but the two chassis are running different software releases, so the pair cannot form yet. Match the software release on both chassis; you don’t need to change the guest passphrase, beacon interval, or client VLAN to resolve this mismatch.
Full Explanation
Stateful switchover on a Catalyst 9800 pair requires both chassis to run the same software release. Here, the redundancy link is up, but the standby is running a different release from the active, so the pair will not form until the releases match. The guest passphrase is a WLAN credential; it is not what the chassis compare to establish the pair. The beacon interval is an over-the-air timer, not a prerequisite for stateful switchover. Shutting the client VLAN does not make different software releases compatible. The exam caveat is that matching releases is necessary, but the redundancy link must also remain healthy; the stem confirms that link is up. As a practical check, put both chassis on the same software release and confirm that the pair forms, without changing the guest passphrase, beacon interval, or client VLAN to address the release mismatch.