27.9.3 Notes on using VLAN debounce function

(1) Notes on Down Delay Time

When a down-determination time is set, the time at which VLANs a VLAN goes down is delayed even when an unrecovered failure occurs. Because communication is not possible during these kinds of delays caused by the VLAN Debounce functionality, set the required value according to the network configuration and operational requirements.

When VLAN communication is no longer possible without a configuration change, such as when suspend is set for a VLAN by the status command, or all VLAN ports are deleted, the time that the VLAN goes down will not be delayed, even when a down-determination time is set.

(2) Notes on Up Delay Time

When an up-determination time is set, if a VLAN that is already up goes down, the time at which it goes back up is delayed. Because a VLAN is initialized when the switch is restarted or the VLAN program is restarted by the restart vlan command, the time that the VLAN goes up will not be delayed, even when an up-determination time is set.

(3) Notes on Delay Time Error

Because a software timer is used for the up and down determination times, the actual determination times might be greater than the time set when CPU usage is high.