Choppy Audio on new 3CX deployment

[dpslusser]

I have a new 3CX deployment that is Pro Licensed. (Getting ready to migrate from old PBX in office).

It is an on premise deployment with the topology looking like this:

SIPtrunk.com---Cable Modem----ASA 5506x----Ubiquiti Gear----Dell PowerEdge (Debian VM 3CX)

Cable Modem is supplying two IP's to the ASA. The 1st IP is for general traffic. 2nd IP is NAT'd to the 3CX.

The 3CX is sitting on the 40VLAN in the office, as well as all our office deskphones. Employee computers sit on 20VLAN, with a rule in the ASA to allow 20 to 40 traffic both ways.

Inner office communication (Ext to Ext) and the 3cx deployment all function great!

Before migrating to SIPtrunk.com and porting all our phone numbers, I asked for a demo line to make sure 3CX is setup and ready to work as intended.



With that out of the way, here is the reason for my post:

After setting up SIPtrunk.com and making a test call (inbound and outbound), the audio was "choppy". Where it sounds like someone is toggling the mute button every 1-2 seconds. For Example, if I say aloud my ABC's, it will sound like this "ABC...GHI...MNO...STU...YZ." And it is from either direction.

Inspect SIP is turned off in the ASA. Made no difference.

I toggled "Audio from PBX". Made no difference.

Bumped up the Codec priority to G722 & 729 and rebooted the deskphone. Made no difference.

I am not an ASA genius and I have other guys familar with Cisco, helping with configuration of the ASA. Together, we reviewed the config with SIPtrunk.com Engineers, working of a Cisco Template, and everything looked great.


Some more intense troubleshooting that I did today:

1. Fired up a demo TWILIO eleastic SIP, adding it to 3CX next to SIPtrunk.com, to test a different SIP provider. TWILIO produces the same results of Choppy audio. [Makes it sound like its not any particular SIP provider]
   
   
2. Using my Android phone 3cx app on LTE (not on WIFI), A call to an extension inside my office, produces the same results of Choppy Audio. [Confirms #1 above, by not being the SIP provider. Also points to a Cisco issue]
   
   
3. Using the ANYconnect VPN app on the android phone above connected to the office VPN, I tested again...NO CHOPPY AUDIO! But, other person calling had a really bad echo.
   
   
4. Calls from behind the ASA (inside the office), work GREAT! And that is across VLAN's. Where the Deskphones lie on the 40 VLAN and the employee computers and WIFI are on the 30VLAN. WIth a rule allowing 30 to see 40, and vis-a-versa. [Because of #2, #3, and #4, it really sounds like something in the ASA. All tests above, point to the ASA].
   

I am running out of patience and idea's.

 

[cobaltit]

So if I fix your problem would you buy your license/maintenance from me and switch to my SIP trunks?

I'm betting that you have your VM under Hyper-V and you didn't read the Hyper-V guide:

https://www.3cx.com/docs/installing-microsoft-hyper-v/

Specifically this part:

Broadcom NetXtreme 1-Gigabit
If the HyperV server uses the above defined network adapter(s), the driver must be updated to the latest version and/or VMq needs to be disabled for those. More information can be found here: https://support.microsoft.com/en-us/kb/2986895

 

[PhatPanda]

You are sure you don't have a split brained situation with your two connections? You checked utilization on your connection? There is a way to set up DSCP QOS for prioritizing outgoing traffic, there should be plenty of info via Google, I used to use an ASA 5510 without issue with 3cx. Next thing to do would be to grab a Wireshark capture, and use the VOIP troubleshoot tools to see if you can get a clue as to where you have issues.

https://www.3cx.com/docs/capture-network-traffic/

 

[PhatPanda]

Good point hadn't though about the VM side, we use VMware and don't worry about that sort of thing

 

[dpslusser]

Running VM ESXi on the Dell where the Debian resides.

Thought about shutting down the Debian server, coping the config to a fresh Debian hosted install and firing it up in the network to see if it changes anything.

 

[dpslusser]

You are sure you don't have a split brained situation with your two connections? You checked utilization on your connection? There is a way to set up DSCP QOS for prioritizing outgoing traffic, there should be plenty of info via Google, I used to use an ASA 5510 without issue with 3cx. Next thing to do would be to grab a Wireshark capture, and use the VOIP troubleshoot tools to see if you can get a clue as to where you have issues.

https://www.3cx.com/docs/capture-network-traffic/

Sorry, thats outside of my knowledge base. Lol. I'll ask my Cisco guy tomorrow.

As for the Wireshark capture, I can do it. Just not sure what to look for.

Will spend some time reading the link you sent.

 

[dpslusser]

So if I fix your problem would you buy your license/maintenance from me and switch to my SIP trunks?

I'm betting that you have your VM under Hyper-V and you didn't read the Hyper-V guide:

I'll tell ya what. Been dealing with this Audio problem for 3-4 weeks now (sporadically trying to troubleshoot and fix when I get time), and I am almost at the point I would take you up on that offer.

Give me a few days yet

 

[dpslusser]

I am installed the Debian 3CX Iso on a miniPC. I will then shutdown the VM running 3CX and plug the miniPC into the network and see if it changes. Maybe it is VMware.