Technical Tip: Improving FortiLink stability using CAPUTP timers

To improve FortiLink stability and reduce failover time, adjust the CAPUTP timers under config switch-controller system.

These parameters control how quickly the FortiGate detects an unreachable FortiSwitch and how fast the CAPUTP process restarts during connectivity issues.

• Configure the CAPUTP ECHO interval to reduce the time required to detect an offline FortiSwitch.

The caputp-echo-interval value is expressed in seconds and supports a range of 8 to 600 seconds:

config switch-controller system
    set caputp-echo-interval 10 <----- The default interval time is 30s.
end

• Configure the maximum number of CAPUTP retransmissions to allow faster CAPUTP timeout and restart.

The caputp-max-retransmit value represents the number of packet retransmissions and supports a range of 0 to 64:

config switch-controller system
    set caputp-max-retransmit 2 <----- The default interval time is 5s.
end

Lower values result in faster failure detection and quicker recovery, which is especially useful in lab environments, FortiLink over WAN scenarios, or environments requiring fast convergence.

These values should be validated in a controlled environment before applying them in production networks.

Note:

FortiLink relies on CAPUTP (a Fortinet variant/extension of CAPWAP) for keepalives, control, and management between FortiGate and FortiSwitch. Default echo/keepalive intervals can be conservative, leading to delayed detection of connectivity issues. Tuning these timers reduces detection time without significantly increasing control-plane load in stable networks.