FortiGate 7000E and 7000F GTP load balancing and fabric channel usage

On a FortiGate 7000F, when GTP load balancing is enabled, GTP tunnels are synchronized over the fabric channel backplane (also called the data channel). The fabric channel is also used for SLBC session synchronization. On a busy FortiGate 7000F that is also load balancing GTP tunnels, the system may experience more lost SLBC heartbeats than normal.

To avoid missed heartbeats, you should increase the max-miss-heartbeats load balancing setting.

For example, when GTP load balancing is enabled, Fortinet recommends setting the max-miss-heartbeats to 40.

config load-balance setting

set max-miss-heartbeats 40

set gtp-load-balance enable

end

For more information about GTP load balancing, see FortiGate-7000F FortiOS Carrier GTP load balancing.