Understanding How Vlans Work - Cisco WS-C2948G-GE-TX Configuration Manual

Configuring VLANs
This chapter describes how to configure virtual LANs (VLANs) on the Catalyst enterprise LAN
switches.
Note For complete syntax and usage information for the commands that are used in this chapter, refer to the
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Command
Reference.
This chapter contains these sections:
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Understanding How VLANs Work

A VLAN is a group of end stations with a common set of requirements, independent of physical location.
A VLAN has the same attributes as a physical LAN, but allows you to group end stations even if the
VLANs are not located physically on the same LAN segment.
VLANs allow you to group ports on a switch to limit unicast, multicast, and broadcast traffic flooding.
Flooded traffic originating from a particular VLAN is only flooded out other ports belonging to that
VLAN.
Before you create VLANs, you must decide whether to use VLAN Trunking Protocol (VTP) or VLAN
Note
Management Policy Server (VMPS) to maintain global VLAN configuration information for your
network. For more information on VTP, see
VMPS, see
Figure 10-1
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Software Configuration Guide—Release 8.2GLX
78-15908-01
Understanding How VLANs Work, page 10-1
VLAN Default Configuration, page 10-4
VLAN Configuration Guidelines, page 10-5
Configuring VLANs on the Switch, page 10-6
Configuring Auxiliary VLANs, page 10-13
Configuring Private VLANs, page 10-16
Chapter 12, "Configuring Dynamic VLAN Membership with VMPS."
shows an example of VLANs that are segmented into logically defined networks.
C H A P T E R
Chapter 9, "Configuring VTP."
10
For more information on
10-1