"Paul Maine Jr." <paulm AT msicc DOT com> writes:
> Todd
> 
> We have Netview NT and there is not a GUI means to accomplish what
> you are asking for. You are wanting to use hysteresis. Hysteresis is
> a means to reduce the number of events generated by quickly changing
> data ( i.e. you desire to filter spikes in your measurements ). I
> don't know if the unix version of Netview has this capability.

Hi Paul! Thanks for the info.  You've got me intrigued, though. 

I'm familiar with the concept of hysteresis (as an EE in former life),
but I guess there's two ways to look at it--what I'll call "value
hysteresis" and "time hysteresis."

The UNIX version of netview does have "value hysteresis"
capability--it's implemented as two values: a threshold trigger level,
and a rearm level.  The difference between them is the amount of
hysteresis in the value supressing multiple alerts on a borderline,
fluctuating reading.

Unforunately, "value hysteresis" doesn't really do anything to filter
out one-time peaks, since the alert would be sent the first time a
sample exceeds a threshold.  In this way, value hysteresis reduces the
occurrence of _repeated_ alerts, but notifies immediately.  I'm not
sure if this is the sort of hysteresis of which you speak.

I just don't see a way to implement the test for two consecutive polls
for being greater than a given value--a metric that aims to capture
only sustained problems (and hence retard when the _first_ alert is
sent in the event of a problem).

Does the NT version have this notion of "time hysteresis" to pass only
sustained problem?