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VTL traffic question

MSBob
Occasional Contributor

VTL traffic question

Good morning, my question is on how VTL call traffic works.  So let’s say I have a VTL set up between two NBXs, when an extension on one system calls an extension on the other system, does the NBX hand the call off to the phones and they communicate directly to each other or does the call traffic still go through the NBX?

 

Basically I have a networking problem somewhere that I am trying to locate and I need to know more about how the calls work before I can figure it out.  The specifics if necessary are as follows:

 

I have a NBX at site A (192.168.0.0 subnet).  Sites A1 (192.168.1.0), A2 (192.168.2.0), and A3 (192.168.3.0) all use this NBX and everything works fine, each site is connected to A via a direct fiber connection.

 

I have a NBX at site B (192.168.9.0).  Sites B1 (192.168.10.0) and B2 (192.168.15.0) use this NBX and are connected to B via direct fiber and everything works fine.

 

Site A and site B are also connected via direct fiber.  I set up a VTL between the two systems and almost everything works perfectly.  Site A and B can grab pri lines from each other.  All 4 A sites can dial extensions at the main B site fine.  My problem is sites B1 and B2.  Calls to extensions at these locations have one way audio, voice traffic makes it to them but does not come back.  What is special about these two sites is that they have VPN gateways set up that connect directly to site A that the computers use.  So I’m just trying to figure out where I’m losing their return voice traffic so I can fix it.

 

Hopefully that made some sense, thank you for any help you can provide.

2 REPLIES
merlin215
Valued Contributor

Re: VTL traffic question

Site A and site B are also connected via direct fiber.  I set up a VTL between the two systems and almost everything works perfectly.  Site A and B can grab pri lines from each other.  All 4 A sites can dial extensions at the main B site fine. 

 

My problem is sites B1 and B2.  Calls to extensions at these locations have one way audio, voice traffic makes it to them but does not come back. 

 

What is special about these two sites is that they have VPN gateways set up that connect directly to site A that the computers use.  So I’m just trying to figure out where I’m losing their return voice traffic so I can fix it.

 

Are these calls failing when site b2 calls b1 and out a local pri or is it just on the VTL ?

Is it both ways on the vtl ? calls outbound to site a ior inbound site a to site b1 or 2 ?

What version of NBC code ?

What type of NBX systems ?

 

make sure that on both sites :

 

2093 , 2094 , 2095, and 2096 UDP ports are open  to start .

tcp port 1040

browser port 80

 

Multicast does not seem to be a culprit yet as it seems to be udp audio . Only conferencing is Multicast audio .

 

Set up messages are from tel tp ncp to ncp to tel .

Audio is peer to peer , tel to tel direct no NCP involved .

bosoxfan
Trusted Contributor

Re: VTL traffic question

To answer your other question, the voice traffic will go from phone to phone and NOT through the NBX.

NBX sets up the calls and tells each phone who to talk to.. audio is phone to phone.

As Merlin stated, make sure you have the ports 2093-2096 open.. also make sure that the phones gateway is correct.