I have a cisco 3800 series router connected on the LAN side to an HP ProCurve 4000m switch. I can only get this connection to come 'up' at 10half (for speed/duplex) if I set both to auto, it negotiates to 10half. All other settings and the interface goes 'down' and will not come back up. I have tried new cables and other ports on the switch as well. Same issue. Any ideas?