HW Failover - what's behind it?
I'm curious about How the HW (serial-based) failover really works.
In their documentation or training materials, F5 only states that there is merely a voltage (no special data) passed over the serial cable and used to detect the failed peer and initiate failover. I wonder how the failover with only a Serial cable (no LAN failover configured) works in situations like:
- manual failover (force standby)
- VLAN or gateway failsafe
- etc
Since there's no failed box in such situations and no special packets are exchanged over the serial cable to announce issues like failed VLAN the only conclusion I made is that the Active BIG-IP box stops sending a voltage across the cable for a short time so the Standby peer detects a failed peer and become the Active unit.
Is this assumption correct?