HP ProCurve 4104GL, Management And Configuration Manual

Page: 264 / 504

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Port-Based Virtual LANs (VLANs) and GVRP
Port-Based Virtual LANs (Static VLANs)
VLAN tagging gives you several options:
■ Since the purpose of VLAN tagging is to allow multiple VLANs on the same
port, any port that has only one VLAN assigned to it can be configured as
“Untagged” (the default).
■ Any port that has two or more VLANs assigned to it can have one VLAN
assignment for that port as “Untagged”. All other VLANs assigned to the
same port must be configured as “Tagged”. (There can be no more than
one Untagged VLAN on a port.)
■ If all end nodes on a port comply with the 802.1Q standard and are
configured to use the correct VID, then, you can configure all VLAN
assignments on a port as “Tagged” if doing so makes it easier to manage
your VLAN assignments, or for security reasons.
For example, in the following network, switches X and Y and servers S1 and
S2 are 802.1Q-compliant. (Server S3 could also be 802.1Q-compliant, but it
makes no difference for this example.)
Figure 11-19. Example of Networked 802.1Q-Compliant Devices with Multiple
VLANs on Some Ports
Red VLAN: Untagged
Red VLAN: Untagged Red VLAN: Untagged
Green VLAN: Tagged
Green VLAN: Tagged Green VLAN: Tagged
Green VLAN only
Server
S1
Server
S2
Server
S3
Green
VLAN Green
VLAN Red
VLAN
Red
VLAN
Switch
"X"
X1
X2
X3
X4
Switch
"Y"
Y1
Y4
Y2 Y5
Y3