speed and duplex

[johnilu]

I have another question for discussion.

What is better:

Static speed and duplex at the switch and static at the host

Static speed and duplex at the switch and auto at the host

Auto speed and duplex at the switch and auto at the host

Auto speed and duplex at the switch and static at the host.

What are your ideas.

 

[vipergg]

In todays networks it is best and easiest to leave both ends as auto . There is only 2 options not 4 as you suggest , both ends have to be auto or you "have" to hardcode both ends to the same speed and duplex. Any of your other scenarios will result in speed/duplex mismatches and very poor performance . For the most part auto on both ends will work ok , of course you can still run into exceptions at which point you can hardcode "both" ends.

 

[johnilu]

I tend to agree at least to a point that there are only two options. I tend to feel that it is better to hard code at both ends. I have had problems with auto negotiation contention as each end tries to figure out what the other is doing. This is probably an artifact of old technology and has been corrected as of late.

Can you point me to any documentation that talks about your recommendations.

Your assistance is appreciated.

 

[helpdeskdan]

vipergg, as usual, is dead on. Usually auto works, but if it doesn't, you can set it manually. Stupid nic cards and old hardware cause can mean you need to set it manually.

And, here's a link if you wish to read more. It even covers CatOS.

http://www.cisco.com/warp/public/473/3.html

 

[McCisco]

They are correct - Auto\auto is the best way. I just learned this lession this weak from the guys

 

[vipergg]

We use auto auto/auto on the networks because on a network of any size it is impossible to hardcode everything and it will also cause problems the next time you move users around and they have the nics at auto then you have mismatches . We support almost 1 a 1000 cisco devices so hardcoding user ports is not practical and to honest it has been a long time since we had any negotiation problems , it is usually outdated nic drivers that is the problem.

 

[helpdeskdan]

jneiberger has a very interesting post on this subject:

http://www.tek-tips.com/viewthread.cfm?qid=1297224&page=1

He advises against using anything but auto/auto

 

[johnilu]

Thank you for all the input. This has realy helped. Thank you all for your time in responding

 

[jneiberger]

Thanks for posting that link to my other post, helpdeskdan! I was just about to re-type my usual rant about this topic, but you saved me the trouble! ;-)

If you're using equipment made in the last four years or so, always use autonegotiation. And ALWAYS set both sides to auto. Some people think you're supposed to set one side to auto and then manually configure the other. That is extremely bad advice.

On modern equipment, auto is your friend.

 

[chieftan]

My 2 pence worth from experience in multiple companies:-

Any end device attatched to a switch = Auto/Auto

Any switch to switch = Hardcode 100/Full (then if any .1q or ISL trunking is required it is easier to complete).