multi locations, NB questions about VOIP

[hoangmn]

If I have 2 locations, one in US and one in China. Should I have 3CX server on each location?
Please note the network latency between US and China is high at 170 ms.

How SIP and VOIP work: let say my 3CX server stay in US, 2 of my remote users using softphone on their trip, one in HK, one in China. When HK call China using softphone, how the traffic going between them? Directly from HK to China or they have to route from HK back to US and to China?

For 2 locations above, if I want to route call to China number from US to my location in China, what equipment should I have?
Assuming I use analog lines in both locations. Do I need only FXO gateway?
If I only have 1 3CX server in US location and buy one FXO gateway for each location.
Can I configure 3CX server so that when I call US, use gateway 1, when I call China, use gateway 2?
Thank you in advance.

 

[amygoda]

Hello,
I think fxo can not support from remote side
So if you know China and Hong Kong VOIP Provider will be better
You need 3cx server in Each Location if your concurent calls is high

If you make a call between to endpoints and server settings for both is
No call record
No server deliver audio

The route must be from the server and traffic will be between endpoints
otherwise the route and traffic will be through the server

 

[tsukraw]

1) I would recommend putting in 2 systems. One at each location that way if the internet at either location is down they will still be able to make local calls. You can then bridge the two 3CX systesm together and be able to call extensions on each. And if you have a PRO license you will have presence information from each.

2) If you use the softphone all of its SIP/RTP voice traffic is going to be routed through the system that it is registered on.
So with your example if you have someone in HK that is registered to the USA system when they call china the voice traffic will go to USA system and then over bridge to china system. There will be a bit more latency on this but really we are talking under a second your users will not notice this.

3)Yes, i think you are talking about something like Lease Cost Routing. Where if you dial a china number in the USA it goes out the phone lines in china? If so and you are usings analog lines (FXO) I would recommend a Patton Gateway. I would look at a VOIP provider if possible and your bandwidth allows it though. Analog longs are dated technology a VOIP provider will give you much more flexibility. But yes short answer of your question is yes if USA call uses USA gateway and China uses China.

 

[tsukraw]

You can target a FXO gateway on a remote network you just need to know how to configure the IP routing correctly.
Its not recommended by 3CX but i think it is not recommended because you require IP routing knowledge to get working.
We have done it a number of times successfully.
But in this case it would be if you didnt have a 3CX server at both locations. If you do have a server at both locations you can just send the traffic across the bridge.

 

[amygoda]

Hello Tucker Sukraw,
I tried it with dyndns an it was not stable

How you make it stable

 

[tsukraw]

@amygoda
I sent you a PM.
We can discuss outside of hoangmn post.

 

[hoangmn]

1) I would recommend putting in 2 systems. One at each location that way if the internet at either location is down they will still be able to make local calls. You can then bridge the two 3CX systesm together and be able to call extensions on each. And if you have a PRO license you will have presence information from each.
-I think 2 systems makes sense only that I have to worry about if that system crash, it will take days to repair.

2) If you use the softphone all of its SIP/RTP voice traffic is going to be routed through the system that it is registered on.
So with your example if you have someone in HK that is registered to the USA system when they call china the voice traffic will go to USA system and then over bridge to china system. There will be a bit more latency on this but really we are talking under a second your users will not notice this.
-Hmm..that's interesting...so going over sea doesn't work very well. Even if I am in the same building in China with my colleague, the call traffic still goes back to US before going to China. I thought the way it works is server provide the IP of each client and point caller to receiver to have direct connect.

3)Yes, i think you are talking about something like Lease Cost Routing. Where if you dial a china number in the USA it goes out the phone lines in china? If so and you are usings analog lines (FXO) I would recommend a Patton Gateway. I would look at a VOIP provider if possible and your bandwidth allows it though. Analog longs are dated technology a VOIP provider will give you much more flexibility. But yes short answer of your question is yes if USA call uses USA gateway and China uses China.

-Analog is stone age but it is reliable. VOIP will be affected if the network is slow.
Thanks Tucker. That is very helpful

 

[leejor]

You could go with one system, it all depends on where the majority of your traffic originates and the costs of hosting at each end, if that is of concern. If you just went with a PBX in the US, you would still have to have a location to put in a gateway in China. You may also want to consider a VoIP provider located in China that is registered to the PBX in the US.

It is essentially the same service as having a PBX hosted on a server with all of the extensions, and a PSTN gateway at a remote site (or two).

The issue, as you mentioned, would be latency, if the audio had to cross the ocean for a "same country" call.

If it is just a single trunk in the remote location, you might consider a single line gateway such as the SPA-3102, unless you have plans to add some lines in the near future.. I have used it successfully, remotely. It should have a fixed public IP at it's end, the PBX can use a static or Dynamic IP (DynDNS), but the gateway IP is set in 3CX. It may work with a Dynamic DNS service at the gateway as well, But I have never tried that.

You could always start with a single installation, and add a second PBX, with bridged trunks if needed.

 

[amygoda]

Hi Leejor,
In dyndns case
which port you think to forward to remote spa-3102

 

[leejor]

Are you talking about forwarding in a router a the remote end where the 3102 is located?

I have never tried putting the 3102 behind a router in a remote trunk set-up, but, if I were and the router had a DynDNS URL, and you were able to put that in as the IP address for the gateway in the trunk settings (I'm not sure if it will accept only an IP address there), the this is what I would try.
The gateway defaults to using port 5061 for the PSTN portion, so that port would have to be forwarded to the IP of the 3102. That same port must be used when you set-up the trunk in 3CX. The voice ports should not require forwarding, in the same way you don't when using a remote extension behind a remote router. That said, you may have to do some experiments and tweaking to be sure that everything works. A lot may depend on the make and model of the remote router as well. Some do not play well with SIP without some "adjustments".

If you run into problems that you are not able to overcome, you could make use of the router built into the 3102, using that to replace the router you were going to place the gateway behind. That would allow the gateway to pick up a public IP, doing away with the need for DynDNS, and still support devices on the LAN side.

 

[ian.watts]

How SIP and VOIP work: let say my 3CX server stay in US, 2 of my remote users using softphone on their trip, one in HK, one in China. When HK call China using softphone, how the traffic going between them? Directly from HK to China or they have to route from HK back to US and to China?

If the PBX Delivers Audio.. else the RTP (audio streams) may not traverse properly between extensions.

For 2 locations above, if I want to route call to China number from US to my location in China, what equipment should I have?
Assuming I use analog lines in both locations. Do I need only FXO gateway?
If I only have 1 3CX server in US location and buy one FXO gateway for each location.
Can I configure 3CX server so that when I call US, use gateway 1, when I call China, use gateway 2?

Yes, a 3102 can be used.. configure SIP similar to a "remote PBX" for Cisco in the documentation.. you need to utilize RPORT across a connection in China back to the PBX. Better, a site-to-site VPN between offices and route VOIP over the VPN for calls to/from China on that ATA. The VPN is more likely to work in China.. less the others.

 

[jpillow]

You do not need a server at both locations this will boil down to usage, where the calls are going (US, China, both), how many users at each location, how many concurrent calls etc.... For example we have remote workers in the Philippines, and Nicaragua connecting back to our office via VPN latency is pretty high on average between 150ms-250ms (no loss in call quality as long as remote worker has suitable data connection) in addition to multiple clients with remote workers/Offices in different parts of the world and in each case it will fall back on their particular needs. Calls will go through the server on extension to extension calls so if you have an employee in HK and he calls the China extension the call will first go back to the US. You do not have to have analog gateways you can use whatever technology you feel most comfortable with, if you go with two systems and the systems are bridged together it will simply be an extension to extension call. Analog will too be affeted if you are have a slow network, so I dont think this should be a consideration when deciding between SIP/analog. Yes you can configure a call to go out on a FXO gateway in either the US or a FXO gateway in China the easiest would be by utilizing two pbx's though this can be done via VPN as well. in this case depending on experience in routing, and VoIP it would be easier to do so with two separate pbx's one at each location