12-19
Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
Chapter12 Configuring Interface Characteristics
Configuring Ethernet Interfaces
Setting the Interface Speed and Duplex Parameters
Beginning in pr ivileged EXEC mod e, follow these s teps to set the speed and duplex mode for a physical
interface:
Use the no speed and no duplex interface configuration commands to return the interface to the default
speed and duplex settings (autonegotiate). To return all interface settings to the defaults, use the default
interface interface-id interface configuration command.
This example shows how to set the interface speed to 10 Mb/s and the duplex mode to half on a
10/100 Mb/s port:
Switch# configure terminal
Switch(config)# interface fasttethernet1/0/3
Switch(config-if)# speed 10
Switch(config-if)# duplex half
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface interface-id Specify the physical interface to be configured, and enter interface
configuration mode.
Step3 speed {10 | 100 | 1000 | auto [10 | 100 |
1000] | nonegotiate}
This command is not available on a 10-Gigabit Ethernet interface.
Enter the appropriate speed parameter for the interface:
Enter 10, 100, or 1000 to set a specific speed for the interface.
The 1000 keyword is available only for 10/100/1000 Mb/s ports.
Enter auto to enable the interface to autonegotiate speed with the
connected device. If you use the 10, 100, or the 1000 keywords
with the auto keyword, the port autonegotiates only at the
specified speeds.
The nonegotiate keyword is available only for SFP module ports.
SFP module ports operate only at 1000 Mb/s but can be
configured to not negotiate if connected to a device that does not
support autonegotiation.
For more information about speed settings, see the “Speed and Duplex
Configuration Guidelines” section on page12-18.
Step4 duplex {auto | full | half} This command is not available on a 10-Gigabit Ethernet interface.
Enter the duplex parameter for the interface.
Enable half-duplex mode (for interfaces operating only at 10 or
100 Mb/s). You cannot configure half-duplex mode for interfaces
operating at 1000 Mb/s.
For more information about duplex settings, see the “Speed and
Duplex Configuration Guidelines” section on page12-18.
Step5 end Return to privileged EXEC mode.
Step6 show interfaces interface-id Display the interface speed and duplex mode configuration.
Step7 copy running-config startup-config (Optional) Save your entries in the configuration file.