Outbound Calls For Two Generic SIP Trunks From The Same Provider

[Mwamba]

We have a client who has been provided with two SIP trunks from their VOIP provider. As there no supported VOIP providers in our country we have to use the Generic VOIP Provider option in 3CX. The provider uses IP based authentication as the trunks are brought directly to the client using a fiber connection. Each trunk is on its own point to point network i.e. the provider assigns the trunk an IP with a /30 subnet mask. The server has three network cards, one for the LAN and the other two for the SIP trunks.

Based on the following post:
https://www.3cx.com/blog/docs/network-configurations-supported-3cx-phone-system/
I have configured the LAN network card with a default gateway and the other two network cards have the IPs assigned by the service provider without a default gateway. The signalling servers and media servers for the two trunks are the same. Therefore, I have created static routes to the signalling and media servers to the default gateway of each trunk. The routes all have the same metric.

Inbound calls work fine and have I two way audio for both trunks. However, outbound calls only work on one trunk because routing is going with one connection. Is there a way for 3CX to choose the route for a call based on the SIP trunk being used in the outbound rule?

 

[lneblett]

Are you indicating that the two fiber connections coming into the property are -
1. Each assigned a different IP (private or public)? I assume public.
2. Each connects back to the same SIP and media server?

Is this a redundant setup where all calls come in on one trunk until and unless one goes down and then the other trunk picks up or, do calls come in randomly on both trunks at the same time?

In 3CX how many SIP trunks did you create? It seems like 2.

While I am a little confused with the description, let's just say that the outbound rules determine which trunk is to be used based upon the criteria you set - extensions, number of digits, strip digits, etc. Assuming you have two trunks created each having a different name, then you could, as an example, indicate that in order to reach T1, the user must precede the dial string with an "8" and to reach T2, the user must precede the string with a "9". Then each trunk would have a rule to strip 1, which would return the dial string to being the number that you originally wished to dial as the "8" and "9" are only used to get to the desired trunk and once there, the extraneous digit is stripped.

You just need to take a look at the rules and determine how you wish to allocate the call paths and modify accordingly.

 

[Mwamba]

I assume public

Each connection is assigned a private IP on a /30 subnet.

2. Each connects back to the same SIP and media server?

Yes the media and SIP servers are the same. For the Registrar and Outbound Proxy fields I entered the IP of the signalling server. The media server is obtained via SDP once the invite is accepted.

Is this a redundant setup where all calls come in on one trunk until and unless one goes down and then the other trunk picks up or, do calls come in randomly on both trunks at the same time?

No it is not a redundant setup, each trunk is meant to be used by a different department in the organization

In 3CX how many SIP trunks did you create? It seems like 2.

Yes I created two sip trunks.

For the outbound rules I am using the extension group and the length of the number being dialed. Inbound calls work okay but for outbound I can only use one trunk for outbound due to the routing on windows.