Per the IEEE standard for 1000base-T, autonegotiation is a requirement.
On switches like the 6509 you can set the speed to 1000 and duplex to full on a gigabit port. My question is this, can anyone point me to some Cisco documentation that identifies what exactly this accomplishes? My assumption is that while you can "force" 1000/full, the port is still doing the autonegotiations required per the standard in order to establish the master-slave relationship and correctly establish timing control for the link. I'm guess that what this really does is do a "gigabit-or-nothing autonegotiation." Thanks for the help.