This document provides the configuration and troubleshooting steps applicable to the creation of Layer 3 interfaces. VLANs divide broadcast domains in a LAN environment. Whenever hosts in one VLAN need to communicate with hosts in another VLAN, the traffic must be routed between them. This is known as inter-VLAN routing. On Catalyst switches it is accomplished by the creation of Layer 3 interfaces (switch virtual interfaces (SVIs) ).

Catalyst switch models 3560, 3750, Catalyst 4500/4000 Series with Sup II+ or later, or Catalyst 6500/6000 Series that run Cisco IOS system software support basic InterVLAN routing features in all their supported software versions. Before you attempt this configuration on a 3550 series switch, ensure that you meet these prerequisites:

InterVLAN routing on the Catalyst 3550 has certain software requirements in order to support interVLAN routing on the switch. See this table in order to determine whether your switch can support interVLAN routing.

The information in this document is based on a Catalyst 3550-48 that runs Cisco IOS Software Release 12.2(44)SE6 EMI.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

In this section, you are presented with the information to configure the features described in this document.

This logical diagram explains a simple interVLAN routing scenario. The scenario can be expanded to include a multi-switch environment if you first configure and test inter-switch connectivity across the network before you configure the routing capability.