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CSM : long delay from standby to active

yves.haemmerli
Level 1
Level 1

Hi,

When resetting the active CSM, the standby CSM immediately takes-over. However, once the primary CSM is back online, it lasts more than 3 minutes for it to become the active active CSM again.

Is it a normal behaviour ?

Here is the primary CSM FT config :

ft group 42 vlan 402

priority 200 alt 100

preempt

After a config-sync, the second CSM is configured like this :

ft group 42 vlan 402

priority 100 alt 200

preempt

Thank you

Yves Haemmerli

1 Accepted Solution

Accepted Solutions

Gilles Dufour
Cisco Employee
Cisco Employee

There is a timer to avoid the active to take over immediately so that it can learn about active flows.

If you have flow replication, you don't want the device that just booted to take over immediately since it would have no knowledge of any connection and would drop all traffic.

Therefore there is a timer to give time to the device to learn about existing connections before taking over.

Gilles.

View solution in original post

1 Reply 1

Gilles Dufour
Cisco Employee
Cisco Employee

There is a timer to avoid the active to take over immediately so that it can learn about active flows.

If you have flow replication, you don't want the device that just booted to take over immediately since it would have no knowledge of any connection and would drop all traffic.

Therefore there is a timer to give time to the device to learn about existing connections before taking over.

Gilles.

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