Use this Knowledge Script to perform an SNMP table walk along specified columns of an SNMP table. This script raises an event if retrieved values exceed the threshold you set.
NOTE:Because this script walks an SNMP table, do not 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 of the attributes walk 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.
This script attempts to walk the specified attributes on all SNMP devices on which this script has been run, regardless of whether any previous attempts failed. If failures do occur, successful walks on other devices are not discarded.
This script individually collects separate data streams for each SNMP device/data OID pairing. Thus, the total number of data streams collected is the number of devices the Knowledge Script is run on multiplied by the number of data OIDs and the number of rows in the table on each device.
NOTE:Supply either all-numeric SNMP attributes or all-string SNMP attributes because you must choose either a numeric check or string check. SNMP attributes that are octet strings, OIDs, or IP addresses are considered to be string attributes.
If one or more numerical conversions are selected, they are performed in the following order: Multiplication, Division, Delta and Percentage. If Delta and Division are both enabled, integer division is performed, and any remainder is discarded. If Delta is not enabled, real-number division is performed.
Values reported in SNMP Success events show the results of multiplication and division conversions, but not delta or percentage conversions, as these are performed after the Success event has been raised. The final result of all conversions is shown in any threshold-crossing events or reflected in the data streams if data is collected.
This script can be run at intervals to periodically poll SNMP tables. However, if delta calculations are being performed on the retrieved values, the script interval should not be less than one minute, because the accuracy of delta calculations is time dependent and may not produce reliable results at shorter intervals. This unreliability is due to many factors including the accuracy of AppManager job scheduling and network traffic delay. The SyncPollTable Knowledge Script should be used to accurately poll at intervals of less than one minute.
By default, this script retrieves the operational status for all interfaces on a device.
SNMP Device objects
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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Get 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. No processing is performed 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 proxy agent computer has the corresponding MIB available. The default is ifOperStatus. |
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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 get |
Specify the maximum number of table rows to be retrieved. The default is 100. |
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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 retries |
Set the number of retries to attempt if a timeout occurs on an SNMP request. The default is 2 retries. |
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SNMP timeout |
Set the number of seconds to wait for a response before timing out an SNMP request. The default is 5 seconds. |
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OID value check |
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Collect data for OID value? |
Set to Yes to collect data for 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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Calculated units |
If this script is performing numeric conversions, a name for the resulting units calculated can be entered here. If nothing is supplied for this parameter, the default units are the name of the data type retrieved. The default is blank. |
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Calculate delta for numeric OID value? |
Set to Yes to specify that the retrieved values are numeric and the difference between the new value and the previous value should be calculated. Normally this is used to monitor growth of SNMP counter values between iterations. The default is unchecked. Delta calculations are not normalized. Thus, it is usually necessary to perform a division conversion on delta calculations to convert to the desired time units. For example, if the growth of an SNMP counter is being tracked by doing a delta calculation at a script interval of one minute, it is necessary to divide by 60 to track the growth of the counter on a per second basis. If set to Yes, integer math (not floating point math) is used, thus any remainder is discarded. NOTE:Do not enable this option if the script is running at intervals of less than one minute. The results may not be reliable. |
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Use multiplier for numeric OID value? |
Set to Yes to specify that the retrieved values are numeric and should be multiplied by the value in the next parameter. By default, multiplication is not performed on retrieved values. |
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Multiplier value |
If the Use multiplier for numeric OID value? parameter 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 numeric OID value? |
Set to Yes to specify that the retrieved values are numeric and should be divided by the value in the next parameter. If the Calculate delta for numeric OID value parameter has also been enabled, integer division is performed and any remainder is discarded. Otherwise, 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 the Use divisor for numeric OID value? parameter 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 numeric OID value? |
Set to Yes to specify that the retrieved values are numeric and should be converted to a percentage of the Maximum value. 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 the Percentage of numeric OID value? parameter 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) |
This parameter has no effect unless Raise event if threshold exceeded? is enabled. For numeric attributes, specify the maximum threshold value. If this value is exceeded, an event is raised. The threshold value is restricted to whole integer values. The default is 1000. |
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Raise event when minimum threshold not met? |
If Raise event if threshold not met? is enabled, 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 the Raise event if threshold not met? parameter is enabled, specify a minimum value for numeric attributes after any calculations have been performed. If this threshold is not met, an event is raised. The threshold value is restricted to whole integer values. The default is 100. |
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Raise event when returned value equals “Numeric value”? |
Set to Yes to raise an event when the retrieved numeric values equal the value supplied in the Numeric value parameter. If enabled, the check is performed after any mathematical conversions that may have been selected above. |
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Check for “not equal” instead of “equals”? |
Use this parameter to change the function of the previous parameter. To raise an event when the retrieved numeric values do not equal the value supplied in the Numeric value parameter, set to Yes and ensure that Raise event when returned value equals “Numeric value”? is also set to Yes. |
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Numeric value |
Use this parameter only if Raise event when returned value equals “Numeric value”? is enabled. An event is raised if the retrieved SNMP values equal the value you enter here. If Check for “not equal” instead of “equals”? is also enabled, an event is raised if the retrieved SNMP values do not equal the value you enter here. This threshold is restricted to whole integer values. The default is 0. |
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Raise event when returned string equals “String value”? |
Set to Yes to raise an event when the retrieved values equal the value supplied in the String value parameter. Use this parameter to retrieve SNMP attributes that are strings, octet strings, OIDs, or IP addresses. |
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Check for “not equal” instead of “equals”? |
Use this parameter to change the function of the previous parameter. To raise an event when the retrieved values do not equal the value supplied in the String value parameter, set to Yes and ensure Raise event when returned string equals “String value”? is also set to Yes. |
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Do case-insensitive comparison? |
If Raise event when returned string not equal to value? is enabled, set to Yes to specify that the retrieved values should be compared without regard to character case. |
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String value |
Use this parameter only If Raise event when returned string equals “String value”? is enabled. An event is raised if the retrieved string equals the value you enter here. If Check for “not equal” instead of “equals”? is also enabled, an event is raised if the retrieved string does not equal the value you enter here. The default is “String Value”. |
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Event severity when OID 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 events if the SNMP Get or GetNext operation 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 the SNMP operation succeeds. The default is 25. |
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Raise event if SNMP timeout exceeded? |
Set to Yes to raise events 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 period 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. |
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Raise event if delta baseline established? |
If Calculate delta for numeric OID value? has been enabled, set to Yes to raise an event when the initial value is retrieved, setting the baseline for a difference calculation on the next retrieval. |
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Event severity when delta baseline established? |
Set the severity level, from 1 to 40, to indicate the importance of an event in which a delta baseline is established. The default is 25. |