Understanding HSRP Operation on the Catalyst 3650

[Translator]

Use two Catalyst 3650 for HSRP redundancy.

There are two units, #1 and #2, with a high priority of #1.

In this configuration, if you disconnect all the cables in #1 and only connect #1, #2, all HSRPs in #1 will become active.

Do you know anything about this phenomenon?

[M02@rt37]

This issue occurs because HSRP does not inherently detect loss of upstream connectivity if the active router (#1) maintains its link to the standby router (#2).

As a result, #1 stays 'active' even when isolated from the network, causing traffic disruption.

So, use HSRP interface tracking to monitor critical uplinks and lower the active router’s priority if a link goes down, forcing a failover to the standby router. Also, enable preemption to allow #1 to reclaim the active role when its links are restored.  

[Translator]

Thank you very much. It seems that you can switch the route based on the information you gave.

In Catalyst 3560 version 12.2, #1's #2 priority did not change, and #1's State was Init, #2's State was Active, and the path was switched.

Catalyst 3650 In version 16.6, the state of #1 seems to be Active, so has the specification changed or is there a special setting?

→ Sorry, this behavior was a misunderstanding of me, and version 12.2 was doing the same behavior as version 16.6.