Auto negotiate or manual

[neoice]

Hi,

We have over 300 workstations on a 100mb network. Currently everything is set for auto negotiation. I am wondering if it would be better to set all nics and switches to 100full?

the reason being is that i was copying a folder that was 1.5gb from my laptop on to my network at home and it was taking ages so I decided to turn both nics on to 100full and the data transfered incredibly faster.

Is this a wise move or could it cause problems.

thanks

neil

 

[mpennac]

Auto-negotiation is one of the biggest problems in our industry. The spec is well defined on how the two ends 'should' figure out what to do, but in many cases they don't do the right thing.

Yes, you should force the speed and duplex to ensure the they are operating at peak performance. Just be sure to force both ends if your are going to start forcing settings. One end forced and the other auto-detect can be worse than auto-auto.

Check out the FAQ's on my website for an explanation of the best settings. I would suggest using a throughput measurement tool such as QCheck or Iperf to measure the connections before and after you make any changes.

mpennac

http://www.netprospecialists.com

 

[jimbopalmer]

I have a FAQ in the ethernet forum on Duplex, I prefer auto-auto except for fiber, but if you use Apple NICs or Cisco switches, their implementaion leaves you with little choice but to hard code duplex

I tried to remain child-like, all I acheived was childish.

 

[haviv512]

It is best to put the NICs to a specific speed/mode than autoneg. That way you do not have to worry about incompatibilities between networking NICs/Switches/equipment.

There is a systemwise/management issue that need to be taken into account: If your NIC is set to a specific speed but the port you are connected is also set to a different speed/mode than they won't be able to talk to each other and either the NIC or the switch/router port need to be reconfigured.
That kind of a situation might happen if some ports in the networks are configured(for some past reason) to another speed/mode and you try to connect the NIC to that port.
In big networks in general the group that handle the infrastructure, switches, routers etc are not always the same people that handle the computers and connect them to the network.