Catalyst 3550 Switch Configuration three layer interface

The Catalyst3550 switch with EMI supports three routes or bridged three-tier interfaces:

Svis: You should configure Svis for any VLAN you want to route traffic to. When you enter a VLAN ID after the interface VLAN Global Configuration command, the Svis is created.

To delete a SVI, use the command:

(global) No interface VLAN

You need to assign a two-tier port to VLANs, see "Configuring VLANs".

Three-layer Ethernet channel port: The Ethernet channel is composed of routed ports. The Ethernet channel port interface is described in "Configuring Ethernet channels."

Routed Port: The routed port is a physical port configured with the interface Configuration command no switchport as three levels.

Note: A three-layer switch can have an IP address assigned to each routed port and SVI.

You can configure the routing and SVI interfaces to be unrestricted on the software;

However, because of hardware limitations, the correlation between this number and the number of other interface features that are configured can affect CPU utilization.

For more information on the special collection Please see the "Optimizing system resources for User Selection feature" section.

All three-tier interfaces require an IP address to be routed through traffic. The following steps show how to configure a three-tier interface and how to assign an IP address to an interface.

Note: If the physical interface is in Layer two mode (default), you must use the No Switchport interface configuration command to put the interface into layer three mode.

Entering a no switchport command disables and re-enable the interface, which may generate messages to the straight port.

In addition, when you use this command to put the interface into layer three mode, you are removing all second-level features of the port.

Starting with privileged mode, the following steps configure a three-tier interface:

?	Command	Purpose
Step 1	Configure Terminal	Enter Global configuration mode
Step 2	interface {fastethernet | gigabitethernet} Interface-id} | {VLAN Vlan-id} | {Port-channel Port-channel-number}	Into the interface configuration mode, and to enter an interface that will be configured as a three-tier interface
Step 3	No Switchport	To get the physical interface into layer three mode
Step 4	IP address ip_address subnet_mask	Configure IP addresses and subnet masks
Step 5	No shutdown
Step 6	End	Return Privileged Mode
Step 7	show interfaces [Interface-id] show IP interface [Interface-id] Show Running-config interface [Interface-id]	Confirm Configuration
Step 8	Copy Running-config Startup-config	(optional) Save your entries to the configuration file

To remove an IP address for an interface, use the command:

(interface) No IP address

This example shows how to configure an interface as a path port and assign an IP address to him:

switch# Configure terminal

Enter configuration commands, one per line. End With cntl/z.

Switch (config) # interface GIGABITETHERNET0/2

Switch (config-if) # no Switchport

Switch (config-if) # IP address 192.168.1.1 255.255.255.0

Switch (config-if) # no shutdown

Switch (config-if) # End

This article from the "Operation and maintenance work Struggle" blog, please be sure to retain this source http://yanghuawu.blog.51cto.com/2638960/744503