I have a customer where we upgraded the WAN connection at a remote site with a 2851 equipped with a 1.5mbps frame-relay to 3.0 mbps multilink frame-relay. The remote site connects to a host 3845 with an un-channelized frame-relay T3 (45mpbs). The customer had no QoS issues at this remote site with their VoIP calls until we added a extra T1 and converted to MFR at the remote. No other sites working off the T3 (all 1.5mpbs pvcs)are having problems. This site will have calls where the audio coming into this site across the WAN will suddenly exprerience high jitter and will be lost.
The caller on the other end still receives the audio stream from the remote site.
The bandwidth utilization of the MFR and T3 is low when this happens. Traffic shaping is not active when this occurs. I see no drops in the queues, no clock slips or lost packets.
Our network surveillance people do not find any drops or errors on the frame switch.
The cisco output interpreter found no problems with the show tech file.
Any suggestions to try?