Cisco Systems 3750E Configuring Layer 3 Interfaces, Configuring Ethernet Management Ports, 11-31

Chapter 11 Configuring Interface Characteristics

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 types 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 switch 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.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02		11-31