Duplex setting for Interface Utilization expressions

[troyj]

I am running NNM 6.2 on Windows 2000 with Nortel Passport 8600 routers. Using the canned reports for utilization I am getting double values for my full duplex interfaces. I know the smarts are there in mibexpr.conf to handle full duplex interfaces but NNM seems determined to see mine as half duplex. If I log snmpCollect I can see it picking IfHDplxUtilization. Does any one know how NNM determines the duplex of an interface? That is, what MIB value does it use?

I'm sure this has been hashed over before but I have been unable to find it in the search...

 

[troyj]

A little more info...

it looks like NNM uses ovexprguru.exe, which calls utilities from ovutil.dll, to determine what expression to use when getting utilization (and other) stats. Perhaps this utility is relying on a table that correlates duplex with something like ifType. I.E. if the ifType is ethernetCsmacd, it must be half duplex. I've modifed the half duplex utilization entries in mibExpr.conf to behave like the full duplex ones (multiply the speed by 2) and I am now getting the correct utilization numbers from the canned reports. However, now if I do have a half duplex connection the utilization numbers are going to be 50% of what they should be. Just another reason to stay away from half duplex connections I guess...