09-27-2006 02:53 AM
If I have a 100Mb full duplex link and it is transmitting at full capacity but receiving a negligible amount of traffic will DFM show this as being 50% utilised or 100%?
You can see my quandary, what do I set my threshold to? If I leave it at 40% I could get alarms when the link is transmitting at half capacity and receiving at half capacity i.e. 50% utilization. If I set it at 60% the link could be transmitting at full capacity and receiving negligible traffic, the utilization would be 50+% and not alarmed!
The first of these two situations is ok but I get an alarm, the second is not ok but significantly I do not get an alarm.
Can someone please advise on how DFM calculates utilization and what I should set my threshold to.
Thanks,
Paul
09-27-2006 05:01 AM
Here is the formula ,it is explained here in a general mathematical language ,this calculation shows how current utilization is calculated .
if NetworkAdapterOperational && UtilizationThreshold < 100 &&
MaxSpeed > 0 && DuplexMode != ICIM_NetworkAdapter::UNSPECIFIED
Check
TrafficRate >= 0 && CurrentUtilization > UtilizationThreshold;
CurrentUtilization = ((TrafficRate * 8) / MaxSpeed * 100;
TrafficRate =
= ifInOctetsRate + ifOutOctetsRate; if DuplexMode is HALFDUPLEX
= max(ifInOctetsRate, ifOutOctetsRate); if DuplexMode is FULLDUPLEX
ifInOctetsRate = rate(ifInOctets, PollingInterval);
ifOutOctetsRate = rate(ifOutOctets, PollingInterval);
UtilizationThreshold = 40
09-27-2006 08:20 AM
I take it that the line 'max(ifInOctetsRate, ifOutOctetsRate)' in english is use the maximum of ifInOctetsRate OR ifOutOctetsRate?
If so this is exactly how I would like it to work i.e. calculate the utilisation for either the transmit or recieve, whichever is the greater. This means if sending at 75% and receiving at 30% and the threshold is 60% I will get an alarm for the 75%.
Excellent stuff, where did you get the information from?
09-27-2006 10:20 AM
I believe that is the case, I would need to doublecheck.
I got this information from one of the developers I worked a DFM case with a while back.
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