Understanding Polling Frequency
Each of IP SLA tests has its own schedule that includes test execution frequency. Thus, statistical information collected by the test and exposed via SNMP protocol updates with the same frequency.
However, the structure of SNMP data exposed by IP SLA capable devices assumes that statuses and statistics of all tests are stored in large tables. Each table contains certain piece of status information about all tests. For example, there is an rttMonLatestHTTPOperTable table that contains detailed execution status information about all HTTP tests.
The architecture of Iotellect Network Manager's SNMP device driver, in its order, assumes that SNMP tables are polled as atomic values. Iotellect Server doesn't update information about each test separately, instead it reads whole test statistics tables by using GET BULK requests to optimize performance.
Thus, the custom synchronization period of all Cisco device account variables containing IP SLA statistics should be equal or shorter than the frequency of any test performed by this device. Failure to follow this rule will lead to loss of some IP SLA test results.
Normally, IP SLA module auto-adjusts custom synchronization periods of IP SLA test result tables during test creation or import. However, system administrators should take care of matching test frequencies to the synchronization periods if some manual changes are performed to the device-side or server-side test configuration.
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