3Com TR manual VLANs, Advantages of Vlan

1-18CHAPTER 1: OVERVIEW

Cut-thru mode. The default mode for the Switch 2000 TR is Dynamic Cut-thru.

VLANs

A VLAN is defined as a group of location- and topol- ogy- independent devices that communicate as though they were on the same physical LAN. This means that they are not restricted by the hardware that physically connects them, and segments are defined by flexible user groups created by the user. For example, with VLANS, the user can define a net- work according to:

Department Groups—A VLAN could be created for the Marketing Department, another VLAN for the Finance Department, and still another for the Devel- opment Department.

Hierarchical Groups—A VLAN could be created for directors, another for managers, and still another for general staff.

Usage Groups—A VLAN could be created for Email users, another for multimedia users, and so on.

Advantages of VLAN

All 802 media and shared media support VLANs. In addition, implementing VLANs:

■Eases the change of devices

■Helps control broadcast traffic

■Provides extra security

VLANs facilitate the administration of logical groups of stations that can communicate as though they were on the same LAN. VLANs also facilitate moves, adds, and changes of members of logical groups.

Traffic between VLANs is firewalled. This limits the propagation of multicast and broadcast traffic between VLANs.

Each distinct VLAN is uniquely identified throughout the bridged LAN. A consistent representation of a VLAN exists across a VLAN fabric (including ATM). This means that the shared VLAN knowledge of a par- ticular packet remains the same as the packet travels from one point to another.