Cisco Catalyst 3550

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Catalyst 3550 Multilayer Switch Command Reference
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Chapter 2 Catalyst 3550 Switch Cisco IOS Commands
speed
If the speed is set to auto, the switch negotiates with the device at the other end of the link for the speed
setting and then forces the speed setting to the negotiated value. The duplex setting remains as
configured on each end of the link, which could result in a duplex setting mismatch.
If the speed is set to auto and the 10, 100, or 1000 keywords are also used, the port only autonegotiates
at the specified speeds.
If both ends of the line support autonegotiation, we highly recommend the default autonegotiation
settings. If one interface supports autonegotiation and the other end does not, configure duplex and speed
on the other side; do use the auto setting on the supported side.
If both the speed and duplex are set to specific values, autonegotiation is disabled.
Caution Changing the interface speed and duplex mode configuration might shut down and re-enable the
interface during the reconfiguration.
Note For guidelines on setting the switch speed and duplex parameters, see the software configuration guide
for this release.
Examples This example shows how to set the specified interface to 100 Mbps:
Switch(config)# interface fastethernet0/1
Switch(config-if)# speed 100
This example shows how to set a port to autonegotiate at only 10 Mbps:
Switch(config)# interface fastethernet0/1
Switch(config-if)# speed auto 10
This example shows how to set a port to autonegotiate at only 10 or 100 Mbps:
Switch(config)# interface fastethernet0/1
Switch(config-if)# speed auto 10 100
You can verify your settings by entering the show interfaces transceiver properties or the
show
running-config privileged EXEC command.
You can verify your settings by entering the show interfaces privileged EXEC command.
Related Commands Command Description
duplex Specifies the duplex mode of operation for Fast Ethernet and Gigabit
Ethernet ports.
show interfaces Displays the statistical information specific to all interfaces or to a specific
interface