[snmpsim-users] Don't understand how counters work...

[Rich B. <ric...@gm...>]

I don't understand how the counter/numeric variation module works. 

I have an SNMP manager that's retrieving counter data from the simulator, and I want to be able to control the values that it retrieves. I have found that a sine wave makes a very good waveform, because its data values are predictable (and pretty :-). This makes it easy to examine the data visually to know whether it is right or not. 

For example, I want to have the traffic values (e.g. rates, or differences between successive readings) be a sine wave of a certain amplitude, with a certain offset from zero (say peak-to-peak value of the sine wave of 100 units, offset by 100, so the *rate* values range from 50 to 150…)

To do this, I think I need to define a counter (32 or 64 bit) that continually increases by the sine(current time). The delta's between these two values will then approximate a sine wave. I believe this requires a formula of the form:

newValue = prevValue + sin(time)

But I don't see how to set this, either in the parameters of the .snmprec file or in the numeric.py file.

Am I missing something? Many thanks.

Rich Brown
Hanover, NH