Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

voice quality

hi all,

some users are compalining the voice is not clear (a lot of cut-off and muting while speaking), I installed a sniffer in the network but couldn't find the reason, how can i start troubleshooting and find out what the reason of this disturbance?

any advices (QOS,Monitoring,..etc),

i'm using CCM 4.2,7970,7960

6 REPLIES
New Member

Re: voice quality

First of all try to understand which type of calls are affected(call from or to pstn call over the wan etc..)

Are you using dual vlan?

does the problem appera during busy hour or not?

did the voice traffic increase during last days?

New Member

Re: voice quality

Only calls from FXO port are affected.

On the same router I have ISDN PRI and the same H.323 config. It is working OK. I have only one vlan. The problem is connected with IPCC agent desktop. App can not go down automatically when call is disconnected by client. When call is over ISDN PRI, it is OK from the same VG. The problem is connected with CCM or H.323. I have the problem on two CCM 4.1 and two VG, 2811 and old VG200.

Hall of Fame Super Gold

Re: voice quality

Have you set the FXO to the correct impedance? you can run a THL sweep, see:

http://cisco.com/en/US/tech/tk652/tk701/technologies_tech_note09186a0080477a06.shtml

Hope this helps, if so please rate post!

New Member

Re: voice quality

it is only to and from pstn, i have dual VLAN,the problem appears most of the time,and we are only 40 users!

thanks

New Member

Re: voice quality

I think it isn't a QoS problem!

have you isdn link to the pstn?

Bronze

Re: voice quality

If you're using ISDN, check for clock slips on the T1/E1 controller. Mine looks like this:

2821#sh controller t1 0/0/1 brief

T1 0/0/1 is up.

Applique type is Channelized T1

Cablelength is long gain36 0db

Description: PRI to PSTN

No alarms detected.

alarm-trigger is not set

Soaking time: 3, Clearance time: 10

AIS State:Clear LOS State:Clear LOF State:Clear

Version info Firmware: 20051006, FPGA: 20, spm_count = 0

Framing is ESF, Line Code is B8ZS, Clock Source is Line.

CRC Threshold is 320. Reported from firmware is 320.

Data in current interval (791 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Total Data (last 24 hours)

0 Line Code Violations, 0 Path Code Violations,

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

141
Views
0
Helpful
6
Replies