VPN Setup in 4 locations

[PatrickMcLeanCI]

Just need a bit of clarification on my setup and issues I'm experiencing:

I have 4 sites, Host (where my server resides), A, B, and C.

I have VPNs set up between Host and all sites (Host to A, Host to B, Host to C) but not between the sites themselves.

As I understand it, if Site A wants to talk to Site B, I need to enable "PBX Delivers Audio" unless I have a VPN connection between Site A and Site B. I've read another alternative is using Static Routes in the VPN router, which I am looking into as well.

My current issue is sometimes people from different sites having trouble hearing each other (one way audio issues) which from my understanding is due to the lack of communication between the sites. Host extensions have no problem talking to anyone on the system (obviously). My temp solution was to turn on PBX Delivers Audio but I've read this should be used as a last resort. Each location has at least 4 extensions, some locations have 8+ and the host has 10+.

My question is, would plopping an SBC at each site (A, B, and C) resolve this issue as well? It wouldn't really be a problem for me to throw an SBC on a Raspberry Pi and plop it in the server room at each location.

 

[SweetAction]

Note: If you do recording PBX delivers audio is "already" on.

Understand the download to PBX delivers audio is just more resources on the server because the PBX has to... deliver the audio as well.

So if resources isn't an issue on the 3CX server, that works.

The 3CX SBC can be thought of as a VPN connection (3CX server is the VPN server and SBC is VPN client) and then your phone is sending it's traffic to the SBC which then sends it over "that VPN" to the server.

How many 3CX servers do you have? Are you using bridging?

 

[PatrickMcLeanCI]

Just one 3CX server but the only resource that might be limited is network bandwidth. CPU and RAM is not an issue.

Recording is not on so I have to go to each extension to enable PBX delivers audio.

 

[leejor]

With VPN, every device should consider all other devices on the same network, and really should not require the PBX Delivers audio option. I suspect that there is some other network configuration that is causing the one way audio. And, yes, removing the VPN, and using an SBC at each site should resolve this.

 

[SweetAction]

The network bandwidth is going to be roughly the same if you use SBC or if you use PBX delivers audio EXCEPT for extension to extension calls in the same site. SBC will keep that locally whereas PBX delivers audio still sends it to the 3CX server.

With VPN, every device should consider all other devices on the same network, and really should not require the PBX Delivers audio option. I suspect that there is some other network configuration that is causing the one way audio. And, yes, removing the VPN, and using an SBC at each site should resolve this.

The site2site in place is only for the host machines is how I understood it. So the phones don't have a VPN connection