Allied Telesis AT-S101 - Manual (Page 46)

Chapter 3: Virtual LANs
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VLAN Overview
A VLAN is a group of ports on an Ethernet switch that form a logical
Ethernet segment. The ports of a VLAN form an independent traffic
domain where the traffic generated by the nodes of a VLAN remains within
the VLAN.
With VLANs, you can segment your network through the switch’s AT-S101
Management Software and group nodes with related functions into their
own separate, logical LAN segments. These VLAN groupings can be
based on similar data needs or security requirements. For example, you
can create separate VLANs for each department in your company, such
as one for Sales and another for Accounting.
VLANs offer several important benefits:
ˆ Improved network performance
Network performance often suffers as networks grow in size and as
data traffic increases. The more nodes on each LAN segment vying for
bandwidth, the greater the likelihood overall network performance
decreases.
VLANs improve network perform because traffic stays within the
separate, logical LAN segment of the VLAN. The nodes of a VLAN
receive traffic only from nodes of the same VLAN. This reduces the
need for nodes to handle traffic that is not destined for them. It also
frees up bandwidth within all the logical workgroups.
In addition, because each VLAN constitutes a separate broadcast
domain, broadcast traffic remains within the VLAN. This too can
improve overall network performance.
ˆ Increased security
Because data traffic generated by a node in a VLAN is restricted only
to the other nodes of the same VLAN, you can use VLANs to control
the flow of packets in your network and prevent packets from flowing to
unauthorized end nodes.
ˆ Simplified network management
In addition, VLANs can simplify network management. Before the
advent of VLANs, physical changes to the network often had to been
made at the switches in the wiring closets. For example, if an
employee changed departments, changing the employee’s LAN
segment assignment might require a change to the cabling of the
switches.
With VLANS, you can change the LAN segment assignment of an end
node connected to the switch through the AT-S101 software. Also, you