Question

A network engineer is troubleshooting intermittent voice quality complaints (choppy audio and jitter) on calls that traverse a SIP trunk between a CUCM cluster and a remote site across a QoS-enabled WAN. Signaling is stable and calls connect normally, but during periods of high data traffic the RTP streams degrade. Packet captures at the WAN edge show that the voice media packets are arriving with a DSCP value of 0 (Best Effort) instead of EF. Signaling packets are correctly marked. Which action is MOST likely to resolve the media degradation?

Accepted Answer

Verify and correct the DSCP for Audio Calls service parameter on CUCM and ensure the WAN QoS policy trusts/re-marks media to EF

Answer

Increase the SIP trunk's Maximum Audio Bit Rate in the CUCM region configuration to force higher-priority scheduling

Answer

Change the SIP trunk transport protocol from UDP to TCP so media packets inherit the signaling class

Answer

Enable Media Termination Point (MTP) Required on the SIP trunk to consolidate the RTP path through CUCM