To evaluate a network device or link’s readiness to carry VoIP traffic, Vivinet Assessor places the measurements taken during Utilization monitoring into VoIP readiness ratings categories. You can determine how a measurement is rated by changing the result ranges for the Utilization assessment. For more information, see Section 5.2, Determining Assessment Result Ranges and Section 8.4.2, Readiness Ratings.
The topics in this section define each measurement used to determine device and link readiness and discuss how these measurements are taken.
To determine each router’s VoIP readiness, Vivinet Assessor uses SNMP queries to take the following measurements. Each measurement is then rated according to the readiness ratings configured for the Utilization assessment. For more information, see Section 8.4.2, Readiness Ratings and Section 5.2, Determining Assessment Result Ranges.
The Router Measurements section of the VoIP Readiness Assessment report provides the following information:
|
Measurement |
Description |
|---|---|
|
Average memory utilization |
The total memory used, expressed as a percentage of memory capacity, averaged from all polling intervals. |
|
Average CPU utilization |
The average CPU utilization, expressed as a percentage of processor time, averaged from all polling intervals. |
|
Buffer errors |
The number of buffer errors (memory allocation failures) that occurred on the router, averaged from all polling intervals. |
|
CRC errors |
The number of cyclical redundancy check (CRC) errors that occurred on the router, averaged from all polling intervals. NOTE:Some vendors, including Nortel, do not break out interface errors to show CRC errors specifically. In these cases, the overall interface error count is substituted for this metric. |
|
Input queue drops |
The rate at which packets were dropped from a router input queue, expressed as a percentage of all packets that entered the router, averaged from all polling intervals. |
|
Output queue drops |
The rate at which packets were dropped from a router output queue, expressed as a percentage of all packets that exited the router, averaged from all polling intervals. |
When Vivinet Assessor monitors routers, it gathers device statistics from each of a router’s individual interfaces. For many metrics, the values it reports are derived from an average of all measurements, from all interfaces. For example, for input and output queue drops per hour and CRC errors, the measurements are taken from active interfaces and averaged for the entire router.
Equipment by different vendors gathers and reports on these statistics slightly differently in a few cases. For example, the CRC errors metric taken from routers actually reflects the overall interface error count for Nortel routers because these routers do not break out interface errors to show CRC errors specifically.
To determine each switch’s VoIP readiness, Vivinet Assessor uses SNMP queries to take the following measurements. Each measurement is then rated according to the readiness ratings configured for the Utilization assessment. For more information, see Section 8.4.2, Readiness Ratings and Section 5.2, Determining Assessment Result Ranges.
Some Nortel and Extreme switches do not provide the necessary MIB data for Utilization monitoring. Therefore, values from these switches show no data in the results.
The Switch Measurements section of the VoIP Readiness Assessment report provides the following information:
|
Measurement |
Description |
|---|---|
|
Average backplane utilization |
The switch backplane utilization (expressed as a percentage of backplane bandwidth), averaged from all polling intervals. |
|
Average CPU utilization |
The CPU utilization (expressed as a percentage of processor time), averaged from all polling intervals. |
To determine each WAN or LAN link’s VoIP readiness, Vivinet Assessor uses SNMP queries to take and average the following measurement. The average measurement is then rated according to the readiness ratings configured for the Utilization assessment. For more information, see Section 8.4.2, Readiness Ratings and Section 5.2, Determining Assessment Result Ranges.
The Link Measurements section of the VoIP Readiness Assessment report provides one measurement:
Bandwidth utilization on this link, expressed as a percentage of available bandwidth, or link capacity, averaged from all polling intervals.