CHAPTER
12-1
Cisco Systems IntelligentGigabit Ethernet Switch Modules for the IBM BladeCenter, Software Configuration Guide
24R9746
12
Configuring VLANs
This chapter describes how to configure normal-range VLANs on your Cisco Systems Intelligent
Gigabit Ethernet Switch Module. It includes information about VL AN 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 12-1
•Configuring Normal-Range VLANs, page 12-4
•Configuring Extended-Range VLANs, page 12-11
•Displaying VLANs, page 12-13
•Configuring VLAN Trunks, page 12-14
•Configuring VMPS, page 12-25

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 12-1. 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 Chapt er 9, “Configuring STP”
and Chapter 10, “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 13,
“Configuring VTP.”