Drop Call and outbound voice not working frequently

[Galaxye]

Hello,

I am not exactly sure that is common or not with my recent experience.
Here is the issue that I currently have.

Status
- We've set 3CX free version V16.0.6.641 / Local Hosted (on-premise)
- Firewall Checker Passed
- Port Forwarding is correctly configured
- Provisioning Method - Local
- Trunk Provider - Skyetel

Issue
- Few drop calls while conversation
- Sometimes, we could hear but the other side (public, outside of our network) could not hear (3 out of 10 calls)

I believe it is not coming from 3CX side, but not sure where I should start to investigate.

 

[cobaltit]

So step 1 would be to update your 3CX. You are on Update 6 and Update 8 is the latest. So update to that and then see if the issue persists.

 

[Galaxye]

Hello @cobaltit
Thanks for getting me back.
For updating the major version, do I need to uninstall and install back with v18? or is there any command line or wizard?
On web UI, I do not see any button under the update page.

NVM, I have done to Update 8.
I would see how it is
thanks for your help

 

[ChrisC_3CX]

@Galaxye
If the issue does persists, next step would be to check if 3CX actually sends audio outward, in regards to the audio issue, and to check who of the two, 3CX or SIP Provider is ending the call in regards to the dropped calls issue.

To do this you could use the built-in packet capture feature to capture the traffic sent and received during the time the issue occurs. Please consider going over our training material where we explain how to perform some basic troubleshooting steps using these tools(slide 9-11): https://www.3cx.com/3cxacademy/videos/advanced/basic-troubleshooting/

Note: You can check the video for more info.

 

[Galaxye]

Hello @ChrisC_3CX

I would investigate as you've mentioned and get back here

Thanks for your help.

@cobaltit - No luck from update

 

[Galaxye]

@ChrisC_3CX

Have checked the packet
We set tested twice without making any changes.

Both call made from out of network (public to 3CX)
1st Trial - Local could hear but the public side could not here
2nd Trial - Both sides were okay.

The packet checked - Both ended 200
But I found one different.

When I played the sound with RTP player from Wireshark
1st Trial - could here both side speak, but poor sound quality
2nd Trial - clear

Phone - Grandstream - GRP 2614
3CX - v16.0.8.9 / local

Is this coming from unstable networking or

 

[ChrisC_3CX]

The fact that you performed a packet capture on the 3CX PBX's network interface and could see both incoming and outgoing RTP streams means that the 3CX PBX did indeed send the audio outward. That being said, since the traffic was sent out it's no longer under 3CX's control. The next step may be to confirm that it leaves your network as well by performing packet captures on the network's firewall, or maybe even contact the provider to determine whether the outgoing RTP stream is reaching them too.

Regarding the audio quality, was it both incoming and outgoing streams affected or just one of them? This may or may not be related to the initial issue.

 

[Galaxye]

For the 1st Trial, it was on both ways.

- For the dropping call, I may assume it is coming from the Router.
Currently, my router using dual WAN with Load Balancing: one with DHCP, another one with Static.
I have done the 3CX setup with Static one and I have been using 1 ISP.
But I am assuming that it has been happened since when I got the secondary ISP with DHCP, and the router screwing up as they are sending the packet to the DHCP one when they outward, I guess.

 

[ChrisC_3CX]

That would most definitely cause issues so you might want to look into that and maybe configure it so that 3CX's traffic all goes only through one WAN interface.

Regarding audio quality, the fact that you see it affecting both directions is a bit weird as the incoming audio has yet to go through the PBX since you captured it on the network interface level, meaning it was received in that state already. Was this same call also recorded on the 3CX PBX? Before investigating this any further I would recommend comparing the recording file with what you heard via wireshark just to make sure.

 

[Galaxye]

Thanks for your reply, I would look into the router setting but I am not sure our current router could support choosing a WAN port for outward (cisco RV325). I will definitely check them.

For audio quality;
Actually, I captured the packet at PBX (3CX web interface).
I believe it might be the same issue coming from router as well?

 

[ChrisC_3CX]

Actually, I captured the packet at PBX (3CX web interface).
I believe it might be the same issue coming from router as well?

Yes that is what I meant, even though you are running the packet capture on the 3CX PBX, it is still running on the network interface level, meaning that incoming audio has yet to be processed by 3CX. The same of course cannot be said for outgoing audio as that has already passed through the PBX.

Do bear in mind that in v18 changes and improvements have been made in regards to audio codec selection in order to minimize transcoding and therefore increase audio quality and stability so if the issue is related to transcoding, this might seize being a problem for you once you upgrade when released. However, if the issue is too much of a problem and you cannot wait for v18 to be released, you might want to consider contacting a 3CX Partner to have them help you troubleshoot it.