Cisco Catalyst 4500 Series Command Reference Manual page 297

Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
If the transmission speed on a 16-port RJ-45 Gigabit Ethernet port is set to 1000, the duplex mode is set
to full. If the transmission speed is changed to 10 or 100, the duplex mode stays at full. You must
configure the correct duplex mode on the switch when the transmission speed changes to 10 or 100 from
1000 Mbps.
Changing the interface speed and duplex mode configuration might shut down and reenable the interface
Caution
during the reconfiguration.
Table 2-2
The specified duplex command that is configured with the specified speed command produces the
resulting action shown in the table.
Table 2-2
duplex Command
duplex half or duplex full
duplex half
duplex full
duplex half
duplex full
duplex full
Examples This example shows how to configure the interface for full-duplex operation:
Switch(config-if)# duplex full
Switch(config-if)#
Related Commands Command
speed
interface (refer to Cisco IOS
documentation)
show controllers (refer to Cisco IOS
documentation)
show interfaces
OL-27596 -01
describes the system performance for different combinations of the duplex and speed modes.
Relationship Between duplex and speed Commands
speed Command
speed auto
speed 10
speed 10
speed 100
speed 100
speed 1000
Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.4.0SG and IOS 15.1(2)SG)
Resulting System Action
Autonegotiates both speed and duplex modes
Forces 10 Mbps and half duplex
Forces 10 Mbps and full duplex
Forces 100 Mbps and half duplex
Forces 100 Mbps and full duplex
Forces 1000 Mbps and full duplex
Description
Configures the interface speed.
Configures an interface.
Displays controller information.
Displays interface information.
duplex
2-239