Audio problems with 7912s

[mlarrimore]

I'm having a problem with some of my 7912 phone they have distorted audio that goes into one-way audio after that. The other party say that they hear a robotic sound then they can not hear at all. I have try opening a case with Tac but so far we are running into all kind of walls. Has anyone had this problem, if so have you found a resolve? I had this problem for months, any help will be appreciated.

[mheusinger]

Hi,

distorted voice and/or one-way voice are most of the time QoS problems in the network.

Can you give some more insight into your network and some more info about your qos configs in place?

Regards

Martin

[mlarrimore]

this is how the configuration looks on the ports for the phones.

interface GigabitEthernet7/18

switchport access vlan xxx

switchport trunk encapsulation dot1q

switchport mode access

switchport voice vlan xxx

switchport port-security

switchport port-security maximum 3

switchport port-security aging time 2

switchport port-security violation restrict

switchport port-security aging type inactivity

service-policy output autoqos-voip-policy

qos trust device cisco-phone

qos trust cos

auto qos voip cisco-phone

tx-queue 3

bandwidth percent 33

priority high

shape percent 33

macro description cisco-phone

spanning-tree portfast

spanning-tree bpduguard enable

there are two 4507 switches that the phones are divided between we have 7940s,60s,70s,12s,36s, and 05s. the 7912s are the only phones we're having this problem with.

[mheusinger]

Hello,

do you have the commands

tx-queue 3

bandwidth percent 33

priority high

shape percent 33

on all ports with telephones connected? I am just guessing here, but there are some vague remarks about shaping in the command reference for the Cat4500 at

http://www.cisco.com/en/US/products/hw/switches/ps4324/products_command_reference_chapter09186a00802c31cd.html#wp2011660

What do you try to achieve with it? Can you remove them for testing purposes?

The rest of your config looks just fine to me.

Hope this helps! Please rate all posts.

Regards, Martin

[mlarrimore]

Yes all phone port configuration has that command. I can remove this from one of the phone port and see if that makes a differnce. Thanks.

[mlarrimore]

took out that part of the configuration but the test subject is still having the same issue. any other suggestions that you may have is welcomed. I have this problem for months now and this case has been to almost all the section in TAC.

[rvanderwerf]

Hi,

I've got the same problem.

I've got problems with 7912 phones and a 4507 and a 4506 core switches.

Did you find the solution for your problem ?

I guess it has something to do with QoS, but I'm not sure.

Thanks in advance,

Raymond.

[mlarrimore]

Hi, well after many techs and cases i send a capture conversation to TAC and they remove the audio from the captured traffic and found that the participants in the phone conversation could not hear each other but both audio of them was captured (we can hear both persons saying are you there) so that determined that it was not one-way audio and he suspects that it maybe a routing issue. So i will have to get with my netwrok guys and see what they can come up with. But whatever it is the 7912 are more susceptible to it then the 7940,7960 or 7970. Hope this help i personal had this problem too long.

[rvanderwerf]

Hi,

Thanks for your reaction.

I've found out that the audio problem only exists on nthe 7912G and not on the 7912G-A model.

Would you be so kind to keep me informed about your experiences and results ?

You can use my email-adres: raymond@vosko.nl

I've also made some sniffer traces and when I'm hearing the audio back it sounds good, but still I can reproduce the problem.

I hope I hear from you,

Raymond.