scope:

The present document describes a framework for measurement methodologies and metrics assessing characteristics of RTP-based speech transmission for fixed duration time intervals. This approach can be used to evaluate aspects of speech transmission based on the observed media volume in terms of time units. This facilitates temporal aggregation of metrics and calculation of key performance indicators in a more meaningful way compared to aggregation of conventional call-based metrics.

The present document presents a classification of methods obtaining RTP flow characteristics per fixed time unit and provides examples for actual timeslice metrics as well as aggregation schemes to obtain key performance indicators summarizing metric data related to a set of timeslices.

The focus is on interactive speech transmission in IP-based networks, i.e. Voice over IP (VoIP) communication. Fundamental concepts are potentially also applicable to interactive video communication, video streaming and other forms of continuous RTP-based communication.

The framework introduces a common foundation to exchange information on timeslice metrics for RTP-based speech transmission performance. The intended audience for the present document can be found among service providers, vendors, and users of telephony services.

The reader is assumed to be familiar with the Framework for IP Performance Metrics (IPPM) [i.2] developed by the IETF. The terminology of the IPPM will be used wherever possible and extended when necessary.