User`s guide

AT-S45 User’s Guide
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Tagged and Untagged VLAN Overview
As explained in the VLAN Overview section earlier in this chapter, a
VLAN consists of a group of ports on one or more Ethernet switches that
forms a logical Ethernet segment and an independent broadcast
domain. Traffic generated by the end nodes of a VLAN remains within
the VLAN and does not cross over to the end nodes of other VLANs
unless there is an interconnection device, such as a router or Layer 3
switch.
A VLAN can consist of all the ports on an Ethernet switch, or just a few
ports. A VLAN can also span switches and consist of ports from multiple
Ethernet switches.
The parts that make up a VLAN are:
❑ VLAN name
❑ VLAN Identifier
❑ Untagged ports
❑ Tagged ports
❑ Port VLAN Identifier
VLAN Name Every VLAN in your network should be given a name. The name should
reflect the function of the network devices that are be members of the
VLAN. Examples include Sales, Production, and Engineering. You will be
required to specify a name when you create a VLAN.
VLAN Identifier Each VLAN in a network must be assigned a number. This number is
called the VLAN identifier (VID). This number will uniquely identify each
VLAN in your network. You assign the VID number when you create the
VLAN.
If a VLAN consists of ports located on only one physical switch in your
network, you must assign it a VID unique from all other VLANs in your
network.
In instances where a VLAN spans multiple switches, the VID for the VLAN
must be the same on each switch where a part of the VLAN resides. This
enables the switches to recognize and forward frames belonging to the
same VLAN even though the VLAN spans multiple switches.
For example, if you had a VLAN titled Marketing that spanned three AT-
9410GB switches, you would assign the Marketing VLAN on each switch
the same VID.