Specifications

2-89
Cisco ME 3400 Ethernet Access Switch Command Reference
OL-9640-07
Chapter 2 Cisco ME 3400 Ethernet Access Switch Cisco IOS Commands
duplex
duplex
Use the duplex interface configuration command to specify the duplex mode of operation for a port. Use
the no form of this command to return the port to its default value.
duplex {auto | full | half}
no duplex
Syntax Description
Defaults The default is auto for Fast Ethernet and Gigabit Ethernet ports and for 1000BASE-T small form-factor
pluggable (SFP) modules.
The default is half for 100BASE-FX MMF SFP modules.
Command Modes Interface configuration
Command History
Usage Guidelines This command is only available when a 1000BASE-T SFP module or a 100BASE-FX MMF SFP module
is in the SFP module slot. All other SFP modules operate only in full-duplex mode.
When a 1000BASE-T SFP module is in the SFP module slot, you can configure duplex mode to auto or
full.
When a 100BASE-FX MMF SFP module is in the SFP module slot, you can configure duplex mode to
half or full. Although the auto keyword is available, it puts the interface in half-duplex mode (the
default) because the 100BASE-FX MMF SFP module does not support autonegotiation.
Certain ports can be configured to be either full duplex or half duplex. Applicability of this command
depends on the device to which the switch is attached.
For Fast Ethernet ports, setting the port to auto has the same effect as specifying half if the attached
device does not autonegotiate the duplex parameter.
For Gigabit Ethernet ports, setting the port to auto has the same effect as specifying full if the attached
device does not autonegotiate the duplex parameter.
auto Enable automatic duplex configuration; port automatically detects whether it
should run in full- or half-duplex mode, depending on the attached device mode.
full Enable full-duplex mode.
half Enable half-duplex mode (only for interfaces operating at 10 Mbps or 100 Mbps).
You cannot configure half-duplex mode for interfaces operating at 1000 Mbps or
10,000 Mbps.
Release Modification
12.2(25)EX This command was introduced.