It works by sending SIP registration requests from the RN appliance to the Asterisk servers. If a number of requests are not answered by one server, then calls are automatically redirected to the responding server. Administrators can configure the specific quantity of responses that must fail before voice traffic is redirected.

"The goal here, for SIP-based monitoring, is to make sure that the entire thing as a package is accessible, meaning the access to the machine is available, the access to the stack is good, and the Asterisk itself is up and running," said Ram Ayyakad, CEO and co-founder of Ranch Networks.

A single IP address is used for both the active and backup Asterisk servers, so they do not need to be on the same network. And the 1+1 HA feature allows databases in both servers to be synchronized.

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