Issues with IP Phones (one-sided conversation)

[darkscion0]

Hello, we're currently using a number of i2004 and i2050 phones (about 80 of them) and seem to be getting intermittent one-sided conversations (can hear the agent on the ipphone but agent cannot hear person on other end). We're running a signaling server and a mix of MC32 and MC32S cards. We've engaged our support provider but haven't gotten anywhere yet.

To begin with I'd like to know what the possible root causes are and then I can go from there.

Thanks!

 

[Triton101]

A few things that can cause this:

DSPs
Misconfiguration
CODEC missmatch
Hardware Failure
Network problems
Software
Security settings
Firewall
Patches
Firmware
Loadware


Verify the things you can, make a bunch of calls, that will step you through the DSPs.

Check all the settings on the IP phones, most common cause is a WRONG Gateway setting or the SUBNET MASK setting that causes this.

You can also setup a port mirror on the LAN switch and sniffer the packets to see what you get.... but that is more involved.

__________________________________________________________
Find a job you love and you'll never work a day in your life. - Confucius

 

[darkscion0]

We have more than enough DSP resources and there shouldn't be any network issues. I've been monitoring one of the phone connections specifically. The weird thing is that they all seem to happen at once. Like a lot of people will have the issue at the same time and then be fine for a bit.

Currently the issue is only happening to i2050 users on our VPN. I've been monitoring one of the agents connections and can confirm that they're ping didn't spike at any point even when the issue was happening.

 

[Reusser]

If I were a betting man - would put my money on DSPs

Best way to find is call from an IP to a TDM phone, once you duplicate problem, stay on the line and trace call.

LD 80
.trac 0 xxxx <-- where xxxx is the DN of one of the phones.

Look in trace for VGW TN - Most likely all or part of this card's DSP's are the problem. Disable card. Again test to see if you can duplicate.

calls round robin through the available DSPs so you will have to make enough calls to cycle through them all.


OR

use a maint. set to connect to a dsp just as you would a trunk, if maint set is IP dial a TDM phone. If Maint set is TDM, dial a IP phone. Test each DSP.

 

[darkscion0]

Well we traced a number of calls and they all landed back on a single MC32S card. The puzzling thing is that we have an even larger number of i2004 phones that are using DSP on that specific card and no one else is reporting any issues.

Would it be possible that only specific ports on the card show the issue?

 

[Reusser]

yes - DSPs are in in chipset groups of 4. Could have just 4 dsps on card a problem.

When you have a chance, re-seat card. After card comes back up - test again. If same problem - disable ports that are problem and replace card when you get a spare.

Replaced card will have a different MAC address that will have to be changed in element manager.

 

[Wane47]

you have the wrong gateway ip on the card that is having the problem.

 

[darkscion0]

Verified the card has the correct network settings. What load and command would I use to disable specific ports?

Thanks

 

[Wane47]

LD 32. DISC LOOP SHELF CARD (EX. DISC 4 0 2). I had the same problem once and I had put in the wrong gateway on one of the media cards. If there is a wrong gateway it could be on either end of the call. The best way to find the trouble is keep calling until you get a bad call and trace it in ld 80. The media card in the trace is your problem.

 

[manswar]

Check If your provider have published your IP at his router end, this could also be a reason for one way audio.

If you are managing Customers router then publish your IP range on the Customers Router or inform your customer to publish these IP. this should resolve your issue.

Regards,
Ansar

 

[gwebster]

a lot of people will have the issue at the same time". What is common among those people? I am personally leaning towards something in your data infrastructure.

 

[opt81]

What system are you running these IP phones on? We had a similar problem and it turned out to be resolved by a patch to the ACD Server if they are going through ACD that is.