EDS-728 Series User’s Manual
Featured Functions
3-39
The Virtual LAN (VLAN) Concept
What is a VLAN?
A VLAN is a group of devices that can be located anywhere on a network, but which
communicate as if they are on the same physical segment. With VLANs, you can segment your
network without being restricted by physical connections—a limitation of traditional network
design. As an example, with VLANs you can segment your network according to:
y
Departmental groups
—You could have one VLAN for the Marketing department, another
for the Finance department, and another for the Development department.
y
Hierarchical groups
—You could have one VLAN for directors, another for managers, and
another for general staff.
y
Usage groups
—You could have one VLAN for e-mail users, and another for multimedia
users.
Benefits of VLANs
The main benefit of VLANs is that they provide a network segmentation system that is far more
flexible than traditional networks. Using VLANs also provides you with three other benefits:
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VLANs ease the relocation of devices on networks:
With traditional networks, network
administrators spend much of their time dealing with moves and changes. If users move to a
different subnetwork, the addresses of each host must be updated manually. With a VLAN
setup, if a host on VLAN
Marketing,
for example, is moved to a port in another part of the
network, and retains its original subnet membership, you only need to specify that the new
port is on VLAN
Marketin
g. You do not need to carry out any re-cabling.
y
VLANs provide extra security:
Devices within each VLAN can only communicate with
other devices on the same VLAN. If a device on VLAN
Marketing
needs to communicate
with devices on VLAN
Financ
e, the traffic must pass through a routing device or Layer 3
switch.
y
VLANs help control traffic:
With traditional networks, congestion can be caused by
broadcast traffic that is directed to all network devices, regardless of whether or not they need
it. VLANs increase the efficiency of your network because each VLAN can be set up to
contain only those devices that need to communicate with each other.
