Specifications

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Catalyst 2970 Switch Software Configuration Guide
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Chapter 9 Configuring Interface Characteristics
Configuring Ethernet Interfaces
• When STP is enabled and a port is reconfigured, the switch can take up to 30 seconds to check for
loops. The port LED is amber while STP reconfigures.
Caution Changing the interface speed and duplex mode configuration might shut down and re-enable the
interface during the reconfiguration.
Setting the Interface Speed and Duplex Parameters
Beginning in privileged EXEC mode, follow these steps 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 100 Mbps on Gigabit Ethernet interface 0/3:
Switch# configure terminal
Switch(config)# interface gigabitethernet0/3
Switch(config-if)# speed 100
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
interface interface-id Enter interface configuration mode and the physical interface
identification.
Step 3
speed {10 | 100 | 1000 | auto | nonegotiate} Enter the appropriate speed parameter for the interface:
• Enter 10, 100, or 1000 to set a specific speed for the interface.
Enter auto to enable the interface to autonegotiate speed with the
device connected to the interface.
• The nonegotiate keyword is available only for SFP module ports.
SFP module ports operate only at 1000 Mbps but can be
configured to not negotiate if connected to a device that does not
support autonegotiation.
Note When a 1000BASE-T SFP module is in the SFP module port,
the speed can be configured to 10, 100, 1000, or auto, but not
nonegotiate.
Step 4
duplex {auto | full} Enter the duplex parameter for the interface.
You cannot configure Gigabit Ethernet interfaces to operate in
half-duplex mode.
This command is not available on SFP module ports unless a
1000BASE-T SFP module is inserted, when the mode can then be
configured to auto or full.
Step 5
end Return to privileged EXEC mode.
Step 6
show interfaces interface-id Display the interface speed and duplex mode configuration.
Step 7
copy running-config startup-config (Optional) Save your entries in the configuration file.