Allied Telesis AT-S39 - Manual (Page 119)

AT-S39 User’s Guide
119
VLAN Overview
A virtual LAN (VLAN) is a logical grouping of devices on different physical
LAN segments that allows users to communicate as if they were
physically connected to a single LAN, independent of the physical
configuration of the network.
With VLAN switch management software, you can segment your
network and group nodes with related functions into their own
separate, logical LAN segments. For example, the marketing personnel
in your company may be spread throughout a building. Assigning
marketing to a single VLAN allows marketing personnel to share
resources and bandwidth as if they were connected to the same
segment. The resources of other departments can be invisible to the
marketing VLAN members, accessible, or accessible only to specified
individuals.
VLAN architecture benefits include:
❑ Increased performance
❑ Improved manageability
❑ Increased security
Increased
Performance
In traditional Layer-2 switched environments, broadcast packets are sent
to each and every individual port. VLANs address the limitations of
standard switch segmentation by containing broadcast as well as node-
to-node traffic.
Grouping users into logical networks limits broadcast traffic to users
performing similar functions or users within individual workgroups.
Extraneous traffic, the danger of broadcast storms, router latency, and
data collisions are significantly reduced, and the efficiency of the entire
network is improved.
Improved
Manageability
VLANs provide a fundamental improvement in the design,
administration, and management of LANs. Before the advent of VLANs,
physical changes to a network were made at the switch in the wiring
closet.
For example, if an employee transferred to a new department, changing
that employee’s LAN segment assignment often required a physical
wiring change at the switch.