scope:

The voice services In-Service, Non Intrusive Measurement Device (INMD) measures active speech level, noise level, speech echo path loss and speech echo path delay at four wire points in the network. As such, it can be used to recognize network anomalies if performance and maintenance limits on these parameters can be established. It is recognized that unique transmission limits do not exist since the performance objectives vary with network providers. This report provides a methodology for establishing INMD performance and maintenance limits based on the network provider's particular objectives. Because this methodology is generic, it can also be used for future INMD that measure other service parameters such as analog or digital data, ISDN, packet, etc. performance parameters.

Purpose and Application

The purpose for establishing performance limits is to detect and correct conditions that do not meet network performance objectives. Therefore INMD performance limits should be established consistent with the already established performance objectives as determined by existing intrusive test limits. The purpose for establishing maintenance limits is to proactively detect deteriorating or intermittent conditions that can likely lead to customer dissatisfaction. Therefore INMD maintenance limits should be established to maximize the effectiveness in avoiding future customer complaints. Performance limits are subjective since they are agreed upon by the customer and the service provider, whereas maintenance limits are objectively determined solely by the network provider to maximize the efficiency of the network maintenance process. The corrective action taken to not meeting performance limits is generally that of reacting to a recognized problem that affects customer service while the action taken to not meeting maintenance limits is generally that of taking proactive steps to correct situations that ca lead to service affecting problems (i.e., not meeting performance limits). Therefore maintenance limits are generally more restrictive than performance limits.