Use this Knowledge Script to perform an SNMP table walk along specified columns of an SNMP table. The retrieved table on the device is then polled at short time intervals at every script iteration. Only numeric attributes are polled. For each table row that is polled, this script computes a minimum, maximum, average and standard deviation. This script raised an event if the computed values exceed the threshold you set.
NOTE:Because this script walks an SNMP table, it is normally not necessary to supply an index value on the ODE/OIDs. Supplying just the attribute name (for example, “ifDescr”) is normally sufficient. If only a portion of the table is to be walked, a parameter is available to specify the subset of table indices to walk.
The table walk is performed with iterative GetNext operations. As soon as any attribute walks beyond the end of the table, or the table indices become out of sync, the table walk terminates. If a table is fully populated, all attributes (or table columns) walk beyond the end of the table on the same GetNext operation. However, if the table has missing values, the table indices become out of sync as soon as a missing value is reached. A table walk is terminated when the first missing value is detected.
When this script is run on multiple devices, they are polled successively, not simultaneously. To poll devices simultaneously, create a different job for each device.
NOTE:The number of Polling attempts multiplied by the Polling interval and then multiplied by the number of devices on which the script is run must not exceed the time interval between script iterations. If this value does exceed the interval, the script job aborts because the polling would not be able to complete before the next Knowledge Script job is due to execute.
The script continues polling, regardless of whether any previous attempts failed. At least two polling attempts must succeed in order to report meaningful data.
This script collects separate data streams for each SNMP table row. Thus, the number of data streams is the number of SNMP data OIDs, multiplied by the number of rows in the table, and multiplied by the number of devices on which the script is run. By default, this script polls how many Kilobytes per second are flowing through each interface listed in the ifTable for the SNMP device.
If one or more numerical conversions are selected, they are performed in the following order: Delta, Multiplication, Division and Percentage. When polling growth of SNMP counter values using the Delta option, all values are normalized on a per second basis, regardless of the length of the polling interval. For example, as stated above by default this script calculates the Kilobytes per second flowing through all interfaces in the device. The values reported are Kilobytes per second regardless of the length of the polling interval.
Host System Folder running an AppManager agent
By default, this script runs once.
Set the following parameters as needed:
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Parameter |
How to Set It |
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Polling Table Parameters |
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Descriptive ODE/OIDs |
Supply a list of SNMP Attribute ODEs and/or OIDs. These are descriptive attributes only which are reported in event and data details for reference purposes, and no processing is done on the retrieved values. The attributes chosen should uniquely identify the retrieved row of an SNMP table. The default is “ifIndex, ifDescr”, which identifies the row number and name of a communications interface in the device. |
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Data ODE/OIDs |
Supply a list of SNMP Attribute ODEs and/or OIDs. ODEs can only be used if the SNMP Toolkit module on the proxy agent computer has the corresponding MIB available. The default is “ifInOctets,IfOutOctets”. |
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Optional table indices |
By default, the entire SNMP table is walked. However, supplying a list of the table indices to be walked can restrict the walk. Indices can be a single integer value, or multiple integer values separated by dots; just like a numeric OID value but without a leading dot. For example, “1.10.42.1.47” is a valid table index. |
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Maximum number of table rows to poll |
Specify the maximum number of table rows to be polled. The default is 100. |
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Polling interval |
Specify the time interval between polling attempts during each Knowledge Script iteration. The default is 5 seconds. |
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Polling attempts |
Specify the number of polling attempts to perform during each Knowledge Script iteration. The default is 12. Combined with the default interval of 5 seconds, the script by default polls the SNMP device for 1 minute. The minimum value is 2. |
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SNMP port number |
Specify the UDP port number on the remote SNMP device to which you want to send SNMP requests. The default is 161. |
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SNMP timeout |
Specify the number of seconds to wait for a response before timing out an SNMP request. The default is 5 seconds. |
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Polled Values Check |
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Collect data for polled values? |
Set to Yes to collect data for use in graphs and reports. The data is stored in the AppManager repository. When enabled, returns a data stream for each SNMP device/SNMP attribute pair. The default is unchecked. |
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Polling calculation type |
For each set of polled values, the Average, Minimum, Maximum and Standard Deviation are calculated. Use this parameter to select which calculated value serves as the data point for the retrieved values. |
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Calculated units |
Specify a name to identify the units being polled and calculated by this script. The default is “Kbytes/Sec”. |
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Calculate delta for polled value? |
Set to Yes to specify that the retrieved values should be considered a delta from the value retrieved by the previous polling attempt. The difference between the new value and the previous value is calculated. Normally this is used to monitor growth of SNMP counter values between polling attempts. The default is Yes. When set to Yes, integer math (not floating point math) is used, thus any remainder is discarded. NOTE:When you enable this parameter, this script reports one less polling attempt than was specified for Polling attempts, because the first polling attempt is used to set a baseline for the delta calculations to follow. |
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Use multiplier for polled value? |
Set to Yes to specify that the retrieved values are numeric and should be multiplied by the value in the next parameter. The default is unchecked. |
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Multiplier value |
If Use multiplier for numeric OID value? is enabled, the retrieved SNMP attributes are multiplied by this value before being reported. The default is 1. |
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Use divisor for polled value? |
Set to Yes to specify that the retrieved values are numeric and should be divided by the value in the next parameter. Values are converted to real numbers to perform the division and retain the precision of any remainder. The default is unchecked. |
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Divisor value |
If Use divisor for numeric OID value? is enabled, the retrieved SNMP attributes are divided by this value before being reported. The default is 1. |
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Calculate percentage of polled value? |
Set to Yes to specify that the retrieved values are numeric and should be converted to a percentage of the maximum value supplied in the next parameter. Values are converted to real numbers to perform the percentage calculation and retain the precision of any remainder. Calculated values are restricted to a real number between 0% and 100%. The default is unchecked. |
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Maximum value |
If Calculate percentage of numeric OID value? is enabled, the retrieved SNMP attributes are converted to a percentage of the maximum value entered here. The default is 100. |
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Raise event when maximum threshold exceeded? |
Set to Yes to specify that the retrieved values should be compared against the maximum threshold value supplied in the next parameter. If enabled, the check is performed after any mathematical conversions that may have been selected above. The default is unchecked. |
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Threshold -- Maximum OID value (post-calculation) |
If Raise event when maximum threshold exceeded? is selected, specify a maximum threshold value. If a retrieved value exceeds the threshold, an event is raised. Polling threshold values are real numbers. The default is 1000. |
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Raise event when minimum threshold not met? |
Set to Yes to specify that the retrieved values should be compared against the minimum threshold value supplied in the next parameter. If enabled, the check is performed after any mathematical conversions that may have been selected above. The default is unchecked. |
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Threshold -- Minimum OID value (post-calculation) |
If Raise event when minimum threshold not met? is enabled, specify a minimum threshold value. If a retrieved value fails to meet this threshold, an event is raised. Polling threshold values are real numbers. The default is 100. |
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Event severity when polled value violates check |
Set the event severity level, from 1 to 40, to indicate the importance of an event in which a threshold is crossed or an equality/inequality check fails. The default is 5. |
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Event Notification |
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Raise event if SNMP operation succeeds? |
Set to Yes to raise an event if the SNMP Get or GetNext is successful. The details of the event contain the retrieved data. |
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Event severity when SNMP operation succeeds |
Set the severity level, from 1 to 40, to indicate the importance of an event in which an SNMP operation is successful. The default is 25. |
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Raise event if SNMP timeout exceeded? |
Set to Yes to raise an event if the SNMP Get or GetNext request receives no response from the device, and all retries fail. |
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Event severity when SNMP timeout exceeded |
Set the severity level, from 1 to 40, to indicate the importance of an event in which the SNMP timeout interval is exceeded. The default is 15. |
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Raise event if SNMP Response error received? |
Set to Yes to raise an event if an SNMP Response error is received from the device. The type of error is reported in the event details. |
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Event severity when SNMP Response error received |
Set the severity level, from 1 to 40, to indicate the importance of an event in which an SNMP Response error is received. The default is 10. |