3cx SBC without Internet on Remote Site

[aashwani2010]

Hi Team,
We have a setup where 3CX Enterprise cluster is in centralized DC and have 20 remote sites with 50-100 IP phones at each site.
Now each site has single 3CX SBC. Few sites doesn't have internet and would like to know if IP phones at the site will work.

 

[bitn2]

Are you serious? How should they work? No internet no voip.... :-D

 

[aashwani2010]

. Thanks for prompt Response. However I don't see any dependencies from likes of Cisco over internet at least for internal office to office calling. so in short 3cX SBC at site needs to have internet and there is no way around that ?

 

[bitn2]

Voip means voice over ip... if you dont have internet you dont have any ips... how do you think should the sbc connect to the 3cx?

 

[aashwani2010]

May be I was not clear enough. Centralized 3CX Cluster in our DC and sites are connected over WAN.

 

[precmfg]

internet at least for internal office to office calling

As I understand it, the signaling aspect (establishing the call/session) is handled by the PBX rather than the SBC and requires a connection to the Internet. Even station to station calls hit the Internet first.

 

[bitn2]

Sure, all your telephonie stuff is done by the pbx... so if the remote site has no internet, you dont have a connection to the pbx. How do you thing should this work?

 

[bitn2]

May be I was not clear enough. Centralized 3CX Cluster in our DC and sites are connected over WAN.

If they are connected over wan, they have internet.... What is correct, no internet or they have internet?

 

[SteveITS]

I think OP is saying the sites can connect to the 3CX server over WAN/VPN but devices at those locations cannot connect directly to the Internet.

From memory that may impact things like RPS/provisioning from the manufacturer, and phones setting their own time. I vaguely remember a thread asking that question (what phones needed access to), a while ago, but can't find it in a quick search.

 

[paulodagraca]

Yes SteveITS, i do think you are right.
What i dont understand is the SBC part.

The use of an SBC is to bridge the networks bypassing the firewall.
As this is not the case, the SBC should not be here.
Also the SBC will connect by FQDN and encrypt data, for this it will need dns access and time, so internet access.

Personally, i think this is more like a local installation, where the phones would connect by IP and the VPN network will do the routing to and from the 3CX server.

So yes there are remote sites, but should be seen as one happy network with multiple connected LANs.

This will have some challanges with split dns and correct time on 3CX and Phones.

Paulo

 

[JohnS_3CX]

Without internet none of these things work: Phone provisioning, RPS, NTP, upgrade firmware, download phonebook and logos, reprovision after any changes are made and probably a couple more things I'm forgetting. And that's as a bare minimum.

So unless you are planning on manually setting up each of the 1000-2000 phones one by one, then you need internet.