7.2 Understanding How VoIP Quality is Assessed

To assess VoIP quality, Vivinet Assessor sends realistic traffic across your network and measures the resulting flows. You set up an assessment of VoIP Quality by selecting the type of traffic to send, including the codec used and some other VoIP-specific parameters, and creating call groups to act as senders and recipients of this traffic. A call group consists of two endpoints connected by a VoIP connector, which defines the type and number of calls to be sent between the endpoints on a specified schedule. The following diagram illustrates how Vivinet Assessor and the endpoints work to measure VoIP quality:

In the diagram above, endpoints that belong to call groups are designated by a telephone receiver symbol. All assessment parameters, including, for example, the codec to be emulated, are saved to an assessment within the Assessor SQL database. This database also contains any results from an assessment after it is run.

When you run an assessment, the Console contacts all the endpoints in each call group. The Console sends the endpoints a call script to use, along with the schedule configured for the assessment that is stored in the database. In the drawing above, dashed lines indicate these setup flows. The endpoints then send the information to their partner endpoints within each call group.

As the assessment runs (solid lines in the drawing), the endpoints take measurements and periodically return results to the Console, which stores them in the database (dashed lines, with arrows pointing back to the Console, indicate reporting flows in the drawing). The endpoints always report results using the connection-oriented TCP protocol so that results are not lost. Simulated VoIP traffic uses the RTP protocol.