Onsite PBX with Cloud Backup?

[greatchoice]

Trying to figure out the best way to minimize our customers request for a new system. This is an educational facility.

They are afraid that if we host the server outside the local LAN, if there is any ISP interruption, onsite phone can not communicate with each other. Most if not all faculty have cell phones to reach the outside and they are aware of the APP they can use. But they are looking at worst case scenario. In Florida, hurricanes and storms happen daily. So they are assuming that the fiber line will be cut and the cellular backup may not connect if the tower is down.

The only thing we can think of is to just have redundant ISPs available but im not sure if that is the answer. We want to try and make something where if the main campus has an ISP outage or is dark, we can kick over to the cloud instance where APPs are still available. Seems very difficult to create something like this

 

[NicholasP_3CX]

You are only as good as your internet connection in any case.

An ideal scenario in this situation would be for an onsite PBX. That way in the event of an internet cut the phones internally will still work. Access to the PSTN through the provider would be hindered in that case.

But you can have an onsite PSTN Gateway with 1-2 lines that can be used in an emergency.

The downside to having one PBX on the premises and another in the cloud is that with every small internet glitch the failover will kick in and you will probably have more issues that benefits.

The failover is for machines on the same network.