Allied Telesis AT-8350GB - Manual (Page 39)

AT-8350GB Installation Guide
39
Port-based and
Tagged VLANs
A VLAN is a group of end nodes that form an independent subnetwork.
Each VLAN constitutes a separate broadcast domain, where the frames
of a VLAN are not allowed to cross the VLAN boundary.
VLANs can be extremely useful in improving network performance and
increasing network security. You can create VLANs to group the
workstations, servers, and other networking equipment connected to
your switches into logical workgroups. These VLAN groupings can be
based on similar data needs or security requirements. When networking
devices, such as workstations and servers, are grouped into a VLAN, data
is exchanged between only those members of the group.
Other advantages of VLANs include:
❑ You can group workstations logically or functionally, regardless of
their physical location on the network.
❑ You can change VLAN memberships anytime by software
configuration without moving the workstations physically or
having to move cables from one port to another on the switch.
❑ With VLAN tagging, network servers or other network resources
can be shared among several VLANs without loss of data isolation
or security.
❑ A VLAN can consist of ports limited to a single switch or ports from
multiple switches. This allows you to group together network
devices that, though physically separated by large distances, will
function as if they are a part of the same physical LAN.
The AT-8350GB Fast Ethernet switch supports:
❑ Port-based VLANs
❑ Tagged VLANs
The AT-8350GB Fast Ethernet switch comes configured with a Default
VLAN. All ports on the switch are members of this Default VLAN.
Quality of
Service (QoS)
The AT-8350GB Fast Ethernet switch supports the IEEE 802.1p standard
and Quality of Service. QoS can be important in network environments
where there are time-critical applications, such as voice transmission or
video conferencing, that can be adversely affected by packet transfer
delays.
Prior to QoS, network traffic was handled in a best-effort manner. File
transfer delays did occur, but were mostly transparent to network users.
But with the introduction of time-critical applications, packet transfer
delays can impact performance. For example, delays in packets carrying
voice transmission can result in poor audio quality.