Duplex Settings

[keogk]

This weekend we are going to be doing some reconfiguring of our Switches and was thinking it may be a good time to play with some settings. I was thinking all of our switches ( Cisco 3750-E) Support full duplex and I think most of our servers do as well ( Proliant DL 360's and 380's G1-G6s as well as a rack of Bl460c)

Should I manually set the ports on the switches and the Nics in the boxes to full duplex or should I just leave them at auto. I have read mostly positive things saying yes to set everything to full and I would get better performance. Just wanted to get a feel for how everyone else was doing it

[garrya100]

You'll only see an increase in performance using manual settings if you have two devices that cannot negotiate full speed sucessfully.

 

It doesn't happen as much now, but I still come across some NIC's that can't seem to get it 'right' and you end up having 10Mbs/half duplex instead of 100Mbs/full duplex.

 

The official Cisco line is that auto is the fail safe mode, and you 'auto-not' leave your switchports auto, but configure them as you need to suit your network.

 

My method is to set the switchports to 100/full and let the NIC's be auto, and all works fine. It also means you don't have to set the speed/duplex at the NIC's, if you can at all.

 

That said, mostly switches are set to auto these days and work sucessfully.

Edited October 23, 2009 by garrya100