User Manual
UMN:CLI
V8102
309
VLAN Tag
A VLAN tag is a predefined field in a frame that carries the VLAN identifier for that frame.
VLAN tags are always applied by a VLAN-aware device. VLAN-tagging provides a num-
ber of benefits, but also carries some disadvantages.
Advantages
Disadvantages
VLAN association rules only need to be applied
once.
Tags can only be interpreted by VLAN aware devices.
Only edge switches need to know the VLAN as-
sociation rules.
Edge switches must strip tags before forwarding
frames to legacy devices or VLAN-unaware domains.
Core switches can get higher performance by
operating on an explicit VLAN identifier.
Insertion or removal of a tag requires recalculation of
the FCS, possibly compromising frame integrity.
VLAN-aware end stations can further reduce the
performance load of edge switches.
Tag insertion may increase the length of a frame be-
yond the maximum allowed by legacy equipment.
Tab. 9.1
Advantages and Disadvantages of Tagged VLAN
9.1.1.1
Creating VLAN
To open the VLAN Database mode, use the following command.
Command
Mode
Description
vlan database
Global
Opens the VLAN Database mode.
To create a VLAN ID
on user’s network, use the following command.
Command
Mode
Description
vlan VLANS
VLAN
Database
Creates a VLAN by assigning VLAN ID:
VLANS: VLAN ID (2-4094, multiple entries possible)
After a VLAN ID creation on the
VLAN Database
mode, you can enter the
VLAN interface
mode to configure the addtional settings.
To enable/disable a VLAN and set its name, use the following command.
Command
Mode
Description
vlan VLANS state
{
enable
|
disa-
ble
}
VLAN
Database
Enables/disables the VLAN operational state. (default:
enable)
VLANS: VLAN ID (2-4094, multiple entries possible)
vlan VLANS
name NAME
Sets the name of VLAN.
NAME: The ascii name of the VLAN
vlan VLANS
name NAME
[
state
{
enable
|
disable
}]
Enables/disables the VLAN operational state and sets
the name.
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