regularly bad connection on 3CX OnPremise system

[M4rtin]

Hi there,

I operate 7 3CX systems at different locations (partly on-premise, in the data center, or directly at 3CX).


In one system ("Deutsche Telekom" SIP Trunk, Onpremise) there is regularly (not always!) a bad connection with Yealink phones connected via LAN, although other participants in this LAN can make calls via Sipgate / GSWave with the same Internet line without any problems. So I would exclude the internet connection as a cause.

It's a mystery to me why this one system regularly causes problems. It runs on a HyperV with 4 GB Ram and about 10% CPU load. The Internet line has given the following readings:


your ping time
51.50ms

Your measured download rate
264.137 Mbps

Your measured upload rate
41.925 Mbps


I configured the trunk with the recommend settings.

Codec:
G.711 A-law
G722

PBX transmits audio


Do you have any idea what may be the issue here?

 

[ChrisC_3CX]

Have you made sure to follow this guide when deploying this PBX: https://www.3cx.com/docs/installing-microsoft-hyper-v/

Particularly the part about "Time Synchronization on Debian VM" provided this IS a Debian VM.

Also, what exact OS is hyper-v running on and what is the Guest OS and the 3CX Version you're running and how many extensions are configured on this PBX?

Based on your description I take it this is only affecting external calls (incoming or Outgoing) and not internal calls (extension to extension) is that correct? Is the issue apparent on every external call or just some and who of the two parties experiences it, external caller/callee, 3CX user or both? If you could also elaborate on what you mean by "Bad connection" it might prove useful (e.g choppy audio, robotic voice, static, etc).

 

[M4rtin]

Hi, I configured the steps in the guide.

It turns out the sipgate / gswave user also have the same problem, so it might be caused by the internet connection.

The HyperV is running on Windows Server 2012 R2. The 3CX is the running on the newest version on debian 18.0 (Build 314).

The bad connection occours about every third call (only external, there are no internal calls made) and it is a choppy audio and robotic voice. One sipgate / gswave user who phones a lot says she can understand the caller very good but the caller says there is a choppy audio.

 

[ChrisC_3CX]

I'll PM you for a bit more information on this.