CHAPT ER
16-1
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
16
Configuring VLANs
This chapter describes how to configure normal-range VLANs on your Catalyst 2950 or Catalyst 2955 .
It includes information about VLAN modes and the VLAN Membership Policy Server (VMPS).
Note For complete syntax and usage information for the commands used in this chapter, see the command
reference for this release.
The chapter includes these sections:
Understanding VLANs, page 16-1
Configuring Normal-Range VLANs, page 16-4
Configuring Extended-Range VLANs, page 16-11
Displaying VLANs, page 16-13
Configuring VLAN Trunks, page 16-13
Configuring VMPS, page 16-23

Understanding VLANs

A VLAN is a switched network that is logically segmented by function, project team, or application,
without regard to the physical locations of the users. VLANs have the same attributes as physical LANs,
but you can group end stations even if they are not physically located on the same LAN segment. Any
switch port can belong to a VLAN, and unicast, broadcast, and multicast packets are forwarded and
flooded only to end stations in the VLAN. Each VLAN is considered a logical network, and packets
destined for stations that do not belong to the VLAN must be forwarded through a router or bridge as
shown in Figure 16-1. Because a VLAN is considered a separate logical network, it contains its own MIB
information and can support its own implementation of spanning tree. See Chapter 13, “Configuring
STP” and Chapter 14, “Configuring MSTP.”
Note Before you create VLANs, you must decide whether to use VLAN Trunking Protocol (VTP) to maintain
global VLAN configuration for your network. For more information on VTP, see Chapter 17,
“Configuring VTP.”