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Need serious help. New 8831 phones having problems.

Thank you in advance for helping with this.

 

I recently rolled out new 8831 conference phones to replace my old 7937 spider phones, unfortunately the phones are experiencing terrible incoming audio. The phones are at a branch site, connected via MPLS and registered to CUCM 8.6 at HQ. We have a total of 900 7940 phones that have no issues at either location, and bandwidth/congestion is not a problem. The poor incoming audio is happening on every call. Outgoing audio is fine. 8831 phones are having the same issues at several branch sites, but seems more predominant in some. The issue has been described as "static, choppy, distorted audio, with some breakups".

 

I have tested with both G.729 and G.711 without any luck, after using the web interface to grab stats here's what they look like:
 

Remote Address  
Local Address  
Start Time  10:33:26a 
Stream Status  Active 
Host Name  
Sender Packets  7180 
Sender Octets  143600 
Sender Codec  G.729 
Sender Reports Sent  0 
Sender Report Time Sent  00:00:00 
Rcvr Lost Packets  2215 
Avg Jitter  20 
Rcvr Codec  G.729
 
Rcvr Reports Sent  0 
Rcvr Report Time Sent  00:00:00 
Rcvr Packets  7178 
Rcvr Octets  143560 
MOS LQK  2.8657 
Avg MOS LQK  2.3054 
Min MOS LQK  2.0000 
Max MOS LQK  3.0295 
MOS LQK Version  0.95 
Cumulative Conceal Ratio  0.1356 
Interval Conceal Ratio  0.0560 
Max Conceal Ratio  0.2766 
Conceal Secs  140 
Severely Conceal Secs  120 
Latency  40 
Max Jitter  160 

Sender Size  20 ms 
Sender Reports Received  0 
Sender Report Time Received  00:00:00 
Rcvr Size  20 ms 
Rcvr Discarded  1266 
Rcvr Reports Received  0 
Rcvr Report Time Received  00:00:00 

 

As you can see the MOS is pretty bad, jitter and dropped packets seem bad too. Intra-site tests have resulted in better looking numbers. Initially I immediately thought "QoS" but all the other phones are fine and the issue is with INCOMING audio not outgoing. 

 

Any comments on this are appreciated. 

 

Thanks.

 

 

Everyone's tags (3)
1 ACCEPTED SOLUTION

Accepted Solutions
Bronze

Hi, As you can see receiver

Hi,

 

As you can see receiver lost packet count is very high which will cause choppy audio. It looks like you are facing below defect

 

https://tools.cisco.com/bugsearch/bug/CSCuq03746

Also can you make sure codec used is g729r8 not g729br8. g729br8 has inbuilt VAD feature so it will drop some packets. Also disable VAD in any voip dial peer using "no vad" command.

 

Regards,

Mohit Singh

1 REPLY
Bronze

Hi, As you can see receiver

Hi,

 

As you can see receiver lost packet count is very high which will cause choppy audio. It looks like you are facing below defect

 

https://tools.cisco.com/bugsearch/bug/CSCuq03746

Also can you make sure codec used is g729r8 not g729br8. g729br8 has inbuilt VAD feature so it will drop some packets. Also disable VAD in any voip dial peer using "no vad" command.

 

Regards,

Mohit Singh

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