Because nic & switch vendors never seem to implement the autodetect spec
in the same and/or correct way.  Depending on the manufacturer of the
switch/nic, sometimes you have to use auto on both, sometimes you have
to hardcode both, sometimes you have to hard code one but set the other
to auto.  There's very little rhymm, reason, or predictability.  You
just have find out what usually works with your particular combination
of equipment.  This makes it very difficult if you don't have
standardized hardware in your environment, and have to figure this out
for every individual combination of equipment.

The exception to this is if you've got a gigabit nic plugging into a
gigabit switch.  That link virtually always has to be set to "auto" on
both ends if you want to get gigabit speed.


>>> Ray.Louvier AT HALLIBURTON DOT COM 11/30/2005 10:00 AM >>>
Can anyone give the technical reason why auto detect on Server NICs
cause such horrible performance for TSM server backups and restores.
We
have our TSM server NIC set to 100MB Full also our switch Port set to
100 Full but we have users with sorted networks such as 1 GB switches
plugged into 100 M wall jacks and travel across several routers., well
you get my meaning. These people or demanding to know why they take 8
days to restore 6 GB. They have their server NIC set to Auto detect,
They have a 1 GB switch that the server and several others are plugged
into because they want hi speed between these servers. But this switch
plugs into a normal 100 meg wall jack to get to our data center. I
have
instructed them to put the NIC to 100 Full and possibly move off swith
but they want a technical reason why. They are developers.

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