Allied Telesis AT-S87 - Manual (Page 66)

Chapter 7: VLANs
66
Port-based VLAN Overview
As explained in “VLAN Overview” on page 64, a VLAN consists of a group
of ports on an Ethernet switch that form an independent traffic domain.
Traffic generated by the end nodes of a VLAN remains within the VLAN .
A port-based VLAN is a group of ports on a Gigabit Ethernet Switch that
form a logical Ethernet segment.
A port-based VLAN can have a maximum of 30 ports.
The parts of a port-based VLAN in the AT-S87 management software are:
ˆ VLAN name
ˆ Group ID
VLAN Name
To create a port-based VLAN, you must give it 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.
Group ID
Each VLAN in a network must have a unique number assigned to it. This
number is called the Group ID. This number uniquely identifies a VLAN in
the switch.
Each port of a port-based VLAN can belong to as many VLANs as
needed. Therefore, traffic can be forwarded to the members of the groups
to which the port is assigned. For example, port 1 and port 2 are members
of group 1 and ports 1 and 3 are members of group 2. In this case, traffic
from port 1 is forwarded to ports 2 and 3, traffic from port 2 is forwarded
only to port 1, and traffic from port 3 is forwarded only to port 1.
General Rules for
Creating a
Port-based
VLAN
Below is a summary of the general rules to observe when creating a port-
based VLAN.
ˆ Each port-based VLAN must be assigned a name.
ˆ Each port-based VLAN must be assigned to one or more Group IDs. If
a particular VLAN spans multiples switches, each part of the VLAN on
the different switches should be assigned the same Group ID.
ˆ A port-based VLAN that spans multiple switches requires a port on
each switch where the VLAN is located to function as an
interconnection between the switches.
ˆ An AT-GS950/48 Gigabit Ethernet Smart Switch can support up to 48
port-based VLANs.
ˆ A maximum of 30 ports can be used for port-based configurations.