C H A P T E R 13

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) on the Catalyst 3750-E and 3560-E switch. It includes information about VLAN membership modes, VLAN configuration modes, VLAN trunks, and dynamic VLAN assignment from a VLAN Membership Policy Server (VMPS). Unless otherwise noted, the term switch refers to a Catalyst 3750-E or 3560-E standalone switch and to a Catalyst 3750-E switch stack.

Note For complete syntax and usage information for the commands used in this chapter, see the command reference for this release.

The chapter consists of these sections:

Understanding VLANs, page 13-1

Configuring Normal-Range VLANs, page 13-4

Configuring Extended-Range VLANs, page 13-12

Displaying VLANs, page 13-16

Configuring VLAN Trunks, page 13-16

Configuring VMPS, page 13-28

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 a switch supporting fallback bridging, as shown in Figure 13-1. In a switch stack, VLANs can be formed with ports across the stack. 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 18, “Configuring STP.”

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

 

OL-9775-02

13-1

 

 

 

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Cisco Systems 3750E manual Configuring VLANs, Understanding VLANs, 13-1