A Catalyst 9800 pair will not form stateful switchover. The redundancy link shows up, and a device in the middle of that link is dropping the redundancy traffic. What is preventing the pair?
Select an answer to reveal the explanation.
Short Explanation
You can see why the link showing up is not enough: the redundancy traffic the pair needs is being dropped in the middle. Remove that obstacle or stop it from dropping the traffic; a guest passphrase is not what the chassis compare.
Full Explanation
Stateful switchover requires the redundancy traffic to pass, not merely a link light. The device in the middle is dropping that traffic, so the pair will not form even though the redundancy link shows up. A guest passphrase is not something the chassis compare to form the pair. The beacon interval does not have to match between the chassis for the pair to form. A client VLAN does not have to be shut for the pair to form. The key distinction is that an up link and a path that drops redundancy traffic are different facts. As an exam caveat, do not treat link status alone as proof that the redundancy path is working. For a practical check, connect the redundancy ports directly, or remove the middle device or permit the redundancy traffic, then confirm that the pair forms.