8-15
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-03
Chapter 8 Configuring Interface Characteristics
Configuring Layer 2 Interfaces
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 10 Mbps and the duplex mode to half on
FastEthernet interface 0/3 and to verify the configuration:
Switch# configure terminal
Switch(config)# interface fastethernet0/3
Switch(config-if)# speed 10
Switch(config-if)# duplex half
Switch(config-if)# end
Switch# show interfaces fastethernet0/3
FastEthernet0/3 is up, line protocol is down
Hardware is Fast Ethernet, address is 0000.0000.0003 (bia 0000.0000.0003)
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Half-duplex, 10Mb/s
input flow-control is off, output flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output never, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
0 packets output, 0 bytes, 0 underruns
0 output errors, 0 collisions, 2 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
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, or enter
auto or nonegotiate.
Note
The 1000 keyword is available only for 10/100/1000 Mbps
ports. The nonegotiate keyword is available only for
1000BASE-SX, -LX, and -ZX GBIC ports.
Step 4
duplex {auto | full | half}
Enter the duplex parameter for the interface.
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.
