On a FortiGate 7000E or 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 7000E or 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, on a FortiGate 7000E Fortinet recommends setting the
max-miss-heartbeats to 40.
config load-balance setting
set max-miss-heartbeats 40
set gtp-load-balance enable
For more information about GTP load balancing, see FortiGate-7000E FortiOS Carrier GTP load balancing or FortiGate-7000F FortiOS Carrier GTP load balancing.