Failover to Offsite server

[varunbhagaloo]

Hey guys,

I have a client that has two branches being served by 3cx.

This is their current configuration-
Head office:
ISP 1; Public IP 1
3CX Server
15 desk phones
Local SIP Trunk (SIP trunk is located on the LAN)

Branch Office:
ISP 1; Public IP 2
SBC
2 desk phones

5 Smartphone apps (Android & IOS) between both branches.

I would like to set up a secondary 3CX server at the branch office, along with another SIP trunk from a different provider. So if the head office fails, the branch office server can take over.

Proposed configuration-
Head office:
ISP 1; Public IP 1
Main 3CX Server
15 desk phones
Local SIP Trunk Provider 1 (SIP trunk is located on the LAN)

Branch Office:
ISP 2; Public IP 2
Standby 3CX Server
2 desk phones
Local SIP Trunk Provider 2 (SIP trunk is located on the LAN)


Scenario 1- Both sites are up
Extensions & softphones from both head office and branch office can make an receive calls over both SIP trunks.

Scenario 2- Head office is down-
Extensions & softphones from both head office and branch office can make an receive calls over Provider 2 SIP trunk.

Scenario 3- Branch office is down-
Extensions & softphones from both head office and branch office can make an receive calls over Provider 1 SIP trunk.

Is this configuration possible? Will I need a SBC at the branch office for the 2 desk phones, even tough the standby server is located there?

 

[SteveITS]

The 3CX HA config restores the database on the backup so it seems to me you would need both providers on both servers, but then you could set up outbound rules to call out in order. For inbound to work provider 1 would need to forward calls to the number of provider 2.

Or are you looking to have two separate servers and bridge them? But if the server itself is down I don't think a bridge helps them.

What are you defining as "down"?

 

[varunbhagaloo]

'Down' can mean either the server looses power or internet connectivity.

Would the secondary server continue to work if the primary is down in a bridge configuration?

 

[SteveITS]

Would the secondary server continue to work if the primary is down in a bridge configuration?

It would, but the phones connected to the offline server wouldn't function.

It sounds like you want one server, with a failover, and both SIP providers configured. https://www.3cx.com/docs/failover/

 

[varunbhagaloo]

Mmm... Thank you. I saw the doc on failover but also saw other installers had issues with the SIP server on the backup side getting disconnected when a failover event occurs.

If I use bridge mode, would the 3CX app on android /iOS continue to work if the main server is offline?

 

[SteveITS]

With 3CX failover, there is no separate configuration for the backup server...it literally restores the backup from the primary.

In bridge mode there are two separate servers with separate FQDN. https://www.3cx.com/docs/manual/connecting-pbx-bridges/

Another option is to host one 3CX server somewhere with built in high availability, such as a public or private cloud. We host in our data center, or 3CX hosting is available.