• United States
Senior Editor

Voice quality in VoIP

Nov 17, 20032 mins

* RTP Control Protocol Reporting Extensions

Voice quality in VoIP implementations is one of the bugaboos about the technology.  But there is some work underway to help remedy that issue.

Our Technology Update this week is about one of those mechanisms. Known as RTP Control Protocol Reporting Extensions (RTCP XR), the technology defines a standard way to detect VoIP call quality by monitoring a variety of key call ingredients such as packet loss, delay and call quality.

According to our Technology Update author (, the IETF this month published RTCP XR as RFC 3611. 

In a nutshell, our author says  RTCP XR works by exchanging  messages containing key call-quality-related metrics are periodically between IP phones and gateways. This lets a probe or analyzer monitor these metrics midstream to support problem resolution, or be retrieved from a gateway using SNMP. Administrators can use SNMP to retrieve data from each IP gateway, or use midstream probes or analyzers to capture call-quality data to aid in problem resolution.

In addition the set of VoIP performance metrics defined in RTCP XR also form the basis for new draft quality-of-service reporting extensions to leading call-control protocols. This will let IP endpoints report call-quality metrics directly to call managers and softswitches, making integration into call detail records easier, according to our author.

I am sure you’ll be hearing more about this protocol.  For more on this article see: