In earlier releases, Communication Manager duplex configurations required a cable to connect two Communication Manager instances with dedicated Communication Manager server hardware. Starting from Communication Manager Release 7.1 and later, you can physically separate the Communication Manager duplex instances.
For server separation support, the duplex servers must be in the same availability zone (AZ) to ensure that both servers are in the same subnet. Availability zone also allows high-availability (HA), which protects the application from datacenter failures.
The minimum requirements for software duplex connectivity between the two Communication Manager instances are as follows:
Total capacity must be 1 Gbps or more.
The Round-trip packet loss must be 0.1% or less.
The Round-trip delay must be 60 ms when Application Enablement Services is not configured and 30 ms when Application Enablement Services is configured.
The duplication ports of both servers must be on the same LAN/IP subnet.
Duplication link encryption must be disabled for the busy-hour call rates that result in more than 40% CPU occupancy.
To allow memory refresh from active to standby server, CPU occupancy on the active server must be less than 65%.
