You will need 2 PBX servers of the same model with identical hardware including analog and digital cards.
Each server must have its own set of licenses for any commercial modules used.
This article assumes the following:
You have an existing a PBX system that will be your primary server.
- You have an identical PBX system equally licensed that will act as the warm sparebe your secondary server.
- Both servers have identical Analog/PRI/BRI hardware (if used).
- The two servers can communicate on an IP level with each other on port 22.