Duplex , Flow Settings - Recommendations?

[PGPhantom]

I am having a bit of a disagreement with settings etc for our Cisco switches and NICS on servers which are Intel, and Broadcom - Can anyone shed some light on this?

Switch and NIC should be set for 100/Full and not auto-negotiate. Specifically to deal with backups and too much data going to our media servers.

Flow control should be on on both server and Switch? I cannot find much info on this one.

For gigabit NICS, set to auto but flow should still be on.

Does anyone have and proven settings for maximum data flow without collisions etc due to too much data?

 

[routerman]

There is a standardised method for flow control across full duplex ethernet links, 802.3x.

The recommendation is always to nail up the duplex and speed settings, never leave critical links to auto negotiate. However just because you have an FD link you cannot always assume you'll be able to maximise the throughput, the host ethernet drivers have to be capable of supplying data to the card.

Not all cisco switch cards support the flow control, but if it is supported by your hardware then the default for Fast Ethernet is off for Rx and on for Tx, whilst for Gigabit its off for Rx and Desired for Tx.

The Cisco documentation talks about IEEE 802.3z flow control on gigabit ethernet ports.

A good reference site for the different ethernet technologies is

http://www.ethermanage.com/ethernet/ethernet.html