Configuring Intervlan Routing; Understanding How Intervlan Routing Works - Cisco WS-C6506 Software Manual

Configuring InterVLAN Routing

This chapter describes how to configure the Multilayer Switch Feature Card (MSFC) for interVLAN
routing on the Catalyst 6500 series switches.
For complete syntax and usage for the commands that are used in this chapter, refer to the Catalyst 6500
Note
Series Switch Command Reference publication.
This chapter consists of these sections:
•
•
Refer to the FlexWAN Module Port Adapter Installation and Configuration Notes for information about
Note
configuring routing on FlexWAN module interfaces.

Understanding How InterVLAN Routing Works

The network devices in different VLANs cannot communicate with one another without a router to
forward traffic between the VLANs. In most network environments, the VLANs are associated with
individual networks or subnetworks.
For example, in an IP network, each subnetwork is mapped to an individual VLAN. In an IPX network,
each VLAN is mapped to an IPX network number.
Configuring the VLANs helps to control the size of the broadcast domain and keeps the local traffic
local. When an end station in one VLAN needs to communicate with an end station in another VLAN,
interVLAN communication is required. This communication is provided by interVLAN routing. You
configure one or more routers to route traffic to the appropriate destination VLAN.
Figure 12-1
VLAN 20. The router has an interface in each VLAN.
OL-8978-04
Understanding How InterVLAN Routing Works, page 12-1
Configuring InterVLAN Routing on the MSFC, page 12-2
shows a basic interVLAN routing topology. Switch A is in VLAN 10 and Switch B is in
C H A P T E R
Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
12
12-1