Intermittent One Way Audio on Internal Calls

[btedeschi]

Have an on going issue with intermittent one way audio between Cisco phones between 2 offices. Calls are internal extension to extension over a MPLS network and in the middle of the conversation one side of the audio drops out. Sometimes the audio will just come back after a few seconds on it's own. If one of the people reestablishes the call it does not always fix the issue either. So far call manager traces of the calls do not show any issues between the two Cisco phones. usually phones involved are 7960's plugged into 3560 or 3550 POE switches and running on call manager 10.5.1.The MPLS circuit is not taking errors or dropping packets nor is the bandwidth being over utilized. Any feedback that might help lead to a resolution would be much appreciated. 

Thanks!

Brett

[Dennis Mink]

I would still be inclined to say it is QoS related.  And notoriously hard to diagnose. First of all I would verify if your RTP stream has the proper DSCP marking of ef. The easiest way to do that is to call into a Jabber softphone which has wireshark running on it.