On Tue, Dec 8, 2009 at 7:18 AM, Matlock, Kenneth L <MatlockK at exempla.org>wrote: > These days at 1Gb+ Full-Duplex seems to be the 'default' for > auto-negotiation failures. > Thankfully it's even more than a "seems to be" - it's written into the IEEE spec that if duplex negotiation fails then the default is full duplex for 1Gbps, as opposed to HDX for 100Mbps and earlier. Scott