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Catalyst 3750-E and 3560-E Switch Software Configuration Guide
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Chapter11 Configuring Interface Char acteristics
Configuring Layer 3 Interfaces
Switch# show interfaces gigabitethernet1/0/2 description
Interface Status Protocol Description
Gi1/0/2 admin down down Connects to Marketing

Configuring Ethernet Management Ports

To specify the Ethernet management port in the CLI, enter fastethernet0.
To disable the port, use the shutdown interface configuration command. To enable the port, use the no
shutdown interface configuration command.
To find out the link status to the PC, you can monitor the LED for the Ethernet management port. The
LED is green (on) when the link is active, and the LED is off when the link is down. The LED is amber
when there is a POST failure.
To display the link status, use the show interfaces fastethernet 0 privileged EXEC command.
Configuring Layer 3 Interfaces
The Catalyst 3750-E and 3560-E switches support these type s of Layer 3 interfaces:
•SVIs: You should configure SVIs for any VLANs for which you want to route traffic. SVIs are
created when you enter a VLAN ID following the interface vlan global configuration command. To
delete an SVI, use the no interface vlan global configuration command. You cannot delete interface
VLAN 1.
Note When you create an SVI, it does not become active until it is associated with a physical port.
For information about assigning Layer 2 ports to VLANs, see Chapter 13, “Configuring
VLANs.”
•Routed ports: Routed ports are physical ports configured to be in Layer 3 mode by using the no
switchport interface configuration command.
•Layer 3 EtherChannel ports: EtherChannel interfaces made up of routed ports.
EtherChannel port interfaces are described in Chapter 37, “Configuring EtherChannels and
Link-State Tracking.”
A Layer 3 switch can have an IP address assigned to each routed port and SVI.
There is no defined limit to the number of SVIs and routed ports that can be configured in a switc h or in
a switch stack. However, the interrelationship between the number of SVIs and routed ports and the
number of other features being configured might have an impact on CPU usage because of hardware
limitations. If the switch is using its maximum hardware resources, attempts to create a routed port or
SVI have these results:
•If you try to create a new routed port, the switch generates a message that there are not enough
resources to convert the interface to a routed port, and the interface remains as a switchport.
•If you try to create an extended-range VLAN, an error message is generated, and the extended-range
VLAN is rejected.