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CHAPTER
14-1
Catalyst 2950 Desktop Switch Software Configuration Guide
78-14982-01
14
Configuring VLANs
This chapter describes how to configure normal-range VLANs (VLAN IDs 1 to 1005) and
extended-range VLANs (VLAN IDs 1006 to 4094). 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, refer to the command
reference for this release.
The chapter includes these sections:
• Understanding VLANs, page 14-1
• Configuring Normal-Range VLANs, page 14-4
• Configuring Extended-Range VLANs, page 14-12
• Displaying VLANs, page 14-14
• Configuring VLAN Trunks, page 14-15
• Configuring VMPS, page 14-24
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 14-1. Because a VLAN is considered a separate logical network, it contains its own
bridge Management Information Base (MIB) information and can support its own implementation of
spanning tree. See Chapter 11, “Configuring STP” and Chapter 12, “Configuring RSTP and 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 15,
“Configuring VTP.”