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Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
OL-9639-06
Chapter 9 Configuring Interfaces Configuring Ethernet Interfaces
Entering the no port-type or default port-type interface configuration command returns the port to the
default state: UNI for Fast Ethernet ports and NNI for Gigabit Ethernet ports.
This example shows how to change a port from a UNI to an NNI and save it to the running configuration.
Switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# interface fastethernet0/1
Switch(config-if)# port-type nni
Switch(config-if)# no shutdown
5d20h: %SYS-5-CONFIG_I: Configured from console by console
Switch(config-if)# end
Switch# copy running-config startup-config
Configuring Interface Speed and Duplex Mode
Ethernet interfaces on the switch operate at 10, 100, or 1000 Mbps and in either full- or half-duplex
mode. In full-duplex mode, two stations can send and receive traffic at the same time. Normally,
10-Mbps ports operate in half-duplex mode, which means that stations can either receive or send traffic.
Switch models include combinations of Fast Ethernet (10/100-Mbps) ports, Gigabit Ethernet
(10/100/1000-Mbps) ports, and small form-factor pluggable (SFP) module slots supporting SFP
modules.
These sections describe how to configure the interface speed and duplex mode:
• Speed and Duplex Configuration Guidelines, page 9-15
• Setting the Interface Speed and Duplex Parameters, page 9-16

Speed and Duplex Configuration Guidelines

When configuring an interface speed and duplex mode, note these guidelines:
• You can configure interface speed on Fast Ethernet (10/100-Mbps) and Gigabit Ethernet
(10/100/1000-Mbps) ports. You can configure Fast Ethernet ports to full-duplex, half-duplex, or to
autonegotiate mode. You can configure Gigabit Ethernet ports to full-duplex mode or to
autonegotiate. You also can configure Gigabit Ethernet ports to half-duplex mode if the speed is 10
or 100 Mbps. Half-duplex mode is not supported on Gigabit Ethernet ports operating at 1000 Mbps.
• With the exception of when 1000BASE-T SFP modules are installed in the SFP module slots, you
cannot configure speed on SFP module ports, but you can configure speed to not negotiate
(nonegotiate) if connected to a device that does not support autonegotiation.
However, when a 1000BASE-T SFP module is in the SFP module slot, you can configure speed as
10, 100, or 1000 Mbps, or auto, but not as nonegotiate.
On a 100BASE-FX SFP module, you cannot configure the speed as nonegotiate.
Step 3 no shutdown Enable the port, if necessary. By default, UNIs and ENIs are
disabled, and NNIs are enabled.
Step 4 port-type {eni | nni | uni}Change a port to an ENI, NNI, or UNI.
Step 5 end Return to privileged EXEC mode.
Step 6 show interfaces interface-id Verify the interface IEEE 802.3x flow control settings.
Step 7 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose