Media Proxy mode not selected

[HamburgerJungeJr]

Hi,
Currently I'm trying to cofigure a 3CX and we are experiencing some quality issues with calls.
I checked the PCAP log and all RTP-Traffic is routed over the PBX. I checked the follwing document (https://www.3cx.com/blog/docs/media-server/) and I expected that the proxy-mode would be used.

This is my configuration
Router IP: 192.168.99.1 (AVM Fritzbox, All port fowardings configured as in the manual except 5090, I dont want to use the PBX form outside only local network)
Router Public IP: 31.18.*.*
PBX IP: 192.168.99.6
Yealink T48G IP: 192.168.99.203 (Provisioned by 3CX)

On Trunk and Endpoint PBX delivers audio is disabled, Re-Invite and Replace are enabled.
So I think all prerequisites for the second Proxy-Mode option are fulfilled

If I call from the outside I can see in the PCAP-Log an Invite with the external SDP to the PBX IP but the Invite to the phone has a SDP with the PBX-Ip as owner. Also all RTP-Traffic is routed by the PBX.

Is there anything I'm missing to get a direct RTP-connection between my Phone and the callee-phone?

 

[cobaltit]

If the PBX is local and on the same subnet you are looking in the wrong place for call quality issues unless the PBX hardware is WAAAY under spec'd or overloaded. You don't mention what OS, what 3CX version, or if you are using a supported SIP trunk provider. But assuming the box isn't overloaded and you don't have crappy internet my first guess is going to be transcoding.

 

[HamburgerJungeJr]

I'm running the official Debian Image with the latest version (16.0.1078, Free license)
I'm running the PBX under KVM on a QNAP TS-473, 2 Cores , 1GB Ram (Both max 50% usage)
My phone/internet provider is Vodafone Germany (Cable not DSL)

How do I know its using transcoding? In wireshark both SDP use G.711

But if I'm right the PBX should only be involved in the call signalling not in transmitting the audio so the hardware should not be a problem because there are max 2 parallel calls running.

 

[JohnS_3CX]

Hi,

In theory, if the provider sends G.711 and your trunk, pbx settings, phone settings are all set with G.711 as the top priority, then there will be no transcoding and the PBX sends the audio packets straight from the provider to the phone without altering them.

So perhaps you should start by describing what quality issues you face before you look at specific things so we can suggest where/what to look for