Port-based virtual lans (static vlans) – IronPort Systems 4108GL User Manual
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14-4
Port-Based Virtual LANs (VLANs) and GVRP
Port-Based Virtual LANs (Static VLANs)
Po
rt
-Ba
sed V
ir
tual
LANs
(VLAN
s) a
n
d
G
V
RP
Port-Based Virtual LANs (Static VLANs)
VLAN Features
A VLAN is a group of ports designated by the switch as belonging to the same
broadcast domain. (That is, all ports carrying traffic for a particular subnet
address would normally belong to the same VLAN.)
N o t e
This section describes static VLANs, which are VLANs you manually config-
ure with a name, VLAN ID (VID), and port assignments. (For information on
dynamic
VLANs, see “GVRP” on page 14-30.)
Using a VLAN, you can group users by logical function instead of physical
location. This helps to control bandwidth usage by allowing you to group high-
bandwidth users on low-traffic segments and to organize users from different
LAN segments according to their need for common resources.
By default, the Switch 4108GL is 802.1Q VLAN enabled and allow up to 30 port-
based VLANs (default: 8). For information on GVRP, see “GVRP” on page 14-30.
(The 802.1Q compatibility enables you to assign each switch port to multiple
VLANs, if needed, and the port-based nature of the configuration allows
interoperation with older switches that require a separate port for each
VLAN.)
General Use and Operation.
Port-based VLANs are typically used to
enable broadcast traffic reduction and to increase security. A group of net-
work users assigned to a VLAN form a broadcast domain that is separate from
other VLANs that may be configured on a switch. On a given switch, packets
are forwarded only between ports that are designated for the same VLAN.
Thus, all ports carrying traffic for a particular subnet address should be
configured to the same VLAN. Cross-domain broadcast traffic in the switch is
Feature
Default
Menu
CLI
Web
view existing VLANs
n/a
configuring static
VLANs
default VLAN with
VID = 1
configuring dynamic
VLANs
disabled See