CHAPTER
10-1
Software Configuration Guide—Release 12.2(25)SG
OL-7659-03
10
Understanding and Configuring VLANs, VTP, and VMPS
This chapter describes VLANs on Catalyst 4500 series switches. It also describes how to enable the
VLAN Trunking Protocol (VTP) and to configure the Catalyst 4500 series switch as a VMPS client.
This chapter includes the following major sections:
VLANs, page 10-1
VLAN Trunking Protocol, page 10-8
VLAN Membership Policy Server, page 10-17

VLANs

This section includes the following major subsections:
Overview of VLANs, page 10-1
VLAN Configuration Guidelines and Restrictions, page 10-3
VLAN Default Configuration, page 10-4
Configuring VLANs, page 10-4
Note For complete syntax and usage information for the switch commands used in this chapter, refer to the
Catalyst 4500 Series Switch Cisco IOS Command Reference and related publications at
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/index.htm.

Overview of VLANs

A VLAN is a group of devices on one or more LANs that are configured to comm unicate as if they were
attached to the same wire, when in fact they are located on a number of different LAN segments. Because
VLANs are based on logical instead of physical connections, they are extremely flexible.
VLANs define broadcast domains in a Layer 2 network. A broadcast domain is the set of all devices that
will receive broadcast frames originating from any device within the set. Broadcast domains are typically
bounded by routers because routers do not forward broadcast frames. Layer 2 switches create broadcast
domains based on the configuration of the switch. Switches are multiport bridges that allow you to create
multiple broadcast domains. Each broadcast domain is like a distinct virtual bridge within a switch.