Audio cutting out

[Matt Stephens]

I've had a few users complain about audio cutting out briefly. Today I actually had the opportunity to hear it for myself. It cuts out for a second and comes right back on our side. The other participant doesn't notice anything. The call recordings do not have the cuts in audio.

I've found a few other forum posts about the same issue, but none of them have a resolution and are not open for replies.

Has anyone else had this issue and come to a resolution?

3CX is on the latest version and up to date. Phones are Yealink T46S

Thank you in advance

 

[cobaltit]

So the important thing to remember about VoIP is it stands for Voice over Internet Protocol, otherwise known as internet. You've given very little information about your actual setup so we'll have to make some assumptions here. Since you said the audio cuts out on the phones but not the recordings, it's most likely a network/internet quality issue between 3CX and the phones.
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[Matt Stephens]

We shouldn't have any network quality issues; the PBX and IP phones have their own VLAN on (fairly new) Cisco SG-300 switches, and there's only about 50 extensions with average of 8 simultaneous calls.

I suppose a wireshark capture of these calls is in order.

 

[Evolute IT]

We shouldn't have any network quality issues; the PBX and IP phones have their own VLAN on (fairly new) Cisco SG-300 switches, and there's only about 50 extensions with average of 8 simultaneous calls.

I suppose a wireshark capture of these calls is in order.

Your 3CX is local? Not hosted in the Cloud?

If so, yes, WireShark. This will give you a better idea of where the issue is.

Quick guess, have you configured QoS on the switch and your firewall/router?

 

[Matt Stephens]

Yes, it's local. In the switch, yes, I think there is some QoS set up. That would have been done by the provider we bought 3CX through. The firewall (SonicWall TZ600) I was instructed to leave SIP ALG off if I recall correctly, because it causes more problems than it solves.

 

[Evolute IT]

Yes, it's local. In the switch, yes, I think there is some QoS set up. That would have been done by the provider we bought 3CX through. The firewall (SonicWall TZ600) I was instructed to leave SIP ALG off if I recall correctly, because it causes more problems than it solves.

Yes, SIP ALG must be off.

I would make sure in the switch and everywhere that QoS is well configured for VoIP.

 

[cobaltit]

Well SIP ALG on or off doesn't matter for this. ALG causes no-audio or one-way audio problems, not cut-outs. But if everything is on the same LAN then that rules out the the internet, but not necessarily the network. How long has this been in place relative to the issue?

 

[Matt Stephens]

How long has this been in place relative to the issue?

Well this being the first time I've heard it myself (and the first time this user complained about it), I don't know if the previous complaints were the same problem. Mostly got it from one user, who I eventually just provisioned a new phone for, and she said that fixed it. But again, I'm not certain that was the same problem.

I switched the current problem extension to "PBX delivers audio" and we'll see if that does anything. Or would that not have an effect here?

 

[cobaltit]

Sorry I worded that poorly. What I meant is how long have you been using 3CX as it's currently configured before this issue popped up. If it's only one user then it could very well just be a defective phone or bad handset cord.

 

[Matt Stephens]

So I asked around the office, and nobody knows what happened to the phone I pulled that complained of this issue before. The employee experiencing it now is fairly new. I'm starting become fairly certain that it was an issue with the phone, which got set aside until we got a new employee, and that phone was reprovisioned for him. I won't be in the office tomorrow, but Friday I'll swap out his phone for a new one and if that works I'll send his old phone for percussive maintenance. I'll report back with results

 

[cobaltit]

percussive maintenance

Office Space 2?

 

[JohnS_3CX]

the captures should help in this case, and you can also run a capture off the phone interface so you can compare sending side (PBX) with the receiving side (yealink) and at least isolate whether the issue is the local network.