5.2 Determining Assessment Result Ranges

Result ranges for utilization monitoring let you set network- or enterprise-specific standards for utilization levels to determine what is rated “Good,” “Acceptable,” or “Poor” utilization in the final VoIP Readiness Assessment report. Defaults for these ranges have been selected according to IP telephony industry standards, and they differ for each measurement and for each device type. If you are monitoring routers, for example, you can configure result ranges for router-specific metrics, including memory and CPU utilization and buffer errors.

NOTE:You can change result ranges at any time. If you change them during utilization monitoring, the changes should be reflected in the Monitored Devices and Links table.

5.2.1 Changing Result Ranges

As a general rule, run Utilization assessments using the Vivinet Assessor default settings for result ranges. However, some default metrics may not be realistic for the network you are assessing. For example, you may have an overtaxed WAN link through which little VoIP traffic will have to flow. In such a case, you would adjust the average and peak utilization result ranges to higher values.

To increase the average and peak utilization result ranges:

  1. Click the Assess Utilization view tab.

  2. On the Options menu, click Result Ranges.

  3. Click the Links tab.

  4. In the Measurements list, select Average Bandwidth Utilization.

  5. Change the Good: Less than or equal to 30% metric to a higher percentage, such as 50%.

  6. If needed, take the same steps to raise the Acceptable metric.

By increasing the average and peak utilization result ranges, the WAN links on this network will be less likely to receive “Poor” readiness ratings in the VoIP Readiness Assessment reports.

For your assessment, adjust the measurement ranges on the Routers and Switches tabs, as well.

5.2.2 Setting Readiness Ratings

You can also determine how overall network device or link readiness ratings are assigned in a VoIP Readiness Assessment Report. Based on measurements taken during the Utilization assessment, these readiness ratings are determined by the percentage of all measurements taken that fell into each ratings category. For example, you may decide that a router’s VoIP readiness will be considered “Good” only if 95% of all its Utilization measurements fall into the “Good” result ranges you set. Therefore, you would set the result range as follows:

To set the “Good” link readiness rating:

  1. In the Result Ranges dialog box, click the Device/Link Readiness tab.

  2. In the % Good field, type 95 to indicate that “At least 95%” of all router measurements must fall into the “Good” range for the device itself to be rated “Good.”

  3. Click OK.

Vivinet Assessor derives the default result range settings from widely accepted industry practices. For example, it is generally agreed that when average link utilization rises above 50%, VoIP quality is very likely to be poor, due to peak usage spikes. Readiness ratings are based on the result ranges that you configure for Device and Link Readiness.

For more information, see Section 8.6, Reviewing Utilization Assessment Factors and Section 8.4.2, Readiness Ratings.

5.2.3 Restoring Default Ranges

You can, at any time, restore the default results ranges for a switch, a link, or a router.

To restore the Vivinet Assessor default settings for an individual measurement:

  1. Click the Assess Utilization view tab.

  2. On the Options menu, click Result Ranges.

  3. Click the Switches tab (or the Routers tab or the Links tab).

  4. Select the measurement in the list, and then click Restore Defaults for This Measurement.