Full duplex, flow-control

[eyoungren]

This is in relation to the manual ethernet settings in the network pref pane. I was reading a bit on this a couple of weeks ago when I added the Xserve NIC to my G4. It had automatically set itself to this.

The suggestion I read was to turn that off and allow flow-control to happen at the hardware level.

But I'm wondering…I renabled it on my G4 and on the two Minis I have in the garage. And transfer times seem to have dropped. Right now, my MP is making a 900GB transfer to my NAS. Before I enabled this the transfer was looking at 16 hours. Now it's around 2 hours.

I also transferred several gigs from the L09 Mini to my MP in a short time yesterday (flow control was enabled).

I understand what flow control is - but I'm wondering why at a OS level this makes such a difference. Assuming that the hardware I am using has flow-control built in.

Anybody have any thoughts on this?

 

[dextructor]

Anybody have any thoughts on this?

From my experience in the past managing hybrid network between PPC Macs and Windows in a advertising agency, Mac don't are very "friendly" in the sense that the network equipment, protocols, priorities are best treated within OSX than if the network control by hardware only.

There's the "Apple way" of implementing almost everything, and networking isn't exactly an exception, but when replacing OSX with other O.S. the same hardware behaves differently in the same network. Because there's not only one type of Flow Control.

Who's to blame? I don't have the specific answer, because every O.S. has a different approach for dealing with hardware interaction stacks, but the entire network infrastructure need to be complaint with the protocols and everything to be working properly otherwise the O.S. will have major overhead decreasing trying to compensate it.

Some few references about flow control for those who like to know

What is Flow-Control in networking?

Flow Control and Network Performance