Rates have become an essential addition to many of the DataMiner SNMP driver tables since they provide more meaningful statistics than just an increasing counter value. However, the accuracy of the rates does not always live up to expectations. With the upcoming improvements to rate calculations, you can expect more precise results.
For rate calculation, the last two values of a counter are used, together with the time between the two value updates (we call it “delta“). In the current implementation, this delta is received as an average of the whole table. But since an SNMP table is never fully retrieved in one go, this leads to inaccuracies.
For big tables, slower devices and/or slower connections, the difference in time between retrieving the first and last row of a table can get significant. In this case, it is no longer advised to take a single average and use it for the calculation of each row, as the timing is not at all accurate for each individual row.
In the improved bitrate calculations, however, every index can be tracked individually (when the request/response for that specific index happened), leading to a much more precise delta value. Using this improved delta value, will consequently lead to more accurate rate calculations.
We are looking forward to implementing these improvements in future SNMP drivers.