3.2 Basic Configuration of the Switch
3.2.6 Defining link speed

On a Cisco IOS software-based switch, the speed of the ports are set using the speed {10|100|auto} command from the interface mode.

If your switch is a set-based switch, enter the following command in privileged mode to configure the port speed on 10/100-Mbps Fast Ethernet modules:

Switch> (enable) set port speed mod/num 10|100|auto

Mod indicates the port module number.

num indicates the port number.

{10 | 100 | auto} indicates the port speed. If the port is placed in auto, both speed and port duplex will be automatically negotiated.