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Looking for Thoughts on Access Switch port configs

Looking for opinions...

Should I set the PC's to AUTO and the switches to AUTO? Should I set the PC's to AUTO and configure the switch to 100/Full?

We are a network of about 5000 users and deploying new access switches. The old network is old 10meg shared media hubs and we decided long ago to manually set up the PC's and the Hubs and any switchs we may have to 10/Half. Not sure what way to go these days.

What is your opinion on this topic?


New Member

Re: Looking for Thoughts on Access Switch port configs

Hi JC,

with old equipment I have seen several problems coming from the autonegotiation of duplex/speed. Additionally, having the PC set up for half/10, going onto auto on switch would mean reconfig of all machines, in fact you might have problems if the PC is set for half/10 and the switch on auto/auto. I would suggest to config the switch ports initially for half/10 and once the hub->switch migration is completed and all other promes are sorted out, you start reconfig closet by closet starting with the most recent PCs/NICs.

This strategy will allow you to preconfigure the switches and deploy quickly and without glitches (just plug in place of HUBS), and then start doing the nasty and long work of reconfiguring single PCs isolating faults to limited portions of the network

The Speed/duplex negotiation is one of the sore spots even between cisco switches and cisco Pixes (I had a few problems with those).


Re: Looking for Thoughts on Access Switch port configs

Auto-negotiation has come a long way over the last 5 years or so; incompatabilities are much rarer today than they used to be, though they still occur sometimes.

The most important thing is that if you have to either leave both ends of a connection on auto, or manually set both ends. You can't leave one end at auto and manually set the other to full-duplex -- you'll get a duplex mismatch which ruins performance.

I think the best way to go is to leave workstation ports & NICs on auto, and manually set servers and inter-switch/inter-router links to 100/full. This saves you the hassle of having to worry about workstation connections which tend to move around much more often than servers, switches, and routers. Unless they're using really old NICs, I think you'll find that the workstations will successfully auto-negotiate a very high percentage of the time.

Re: Looking for Thoughts on Access Switch port configs

I 100% agree.

Just one useful link for a case of trouble with some NICs:

One good advice from that document:

Don't let power-savers to switch off the NIC while PC "sleeps".



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