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Configuring the Switch
Port-Based Virtual LANs (VLANs)
Configuring the Switch
VLAN Restrictions
■ A port must be a member of at least one VLAN. In the factory default
configuration, all ports are assigned to the default VLAN
(DEFAULT_VLAN).
■ A port can be assigned to several VLANs, but only one of those assign-
ments can be untagged. (The “Untagged” designation enables VLAN oper-
ation with non 802.1Q-compliant devices.)
■ An external router must be used to communicate between VLANs.
■ Duplicate MAC addresses on different VLANs are not supported and can
cause VLAN operating problems. These duplicates are possible and com-
mon in situations involving Sun workstations with multiple network
interface cards, with DECnet routers, and with certain Hewlett-Packard
routers using OS versions earlier than A.09.70 where any of the following
are enabled:
•IPX
•IP Host-Only
•STP
•XNS
•DECnet
Currently, the problem of duplicate MAC addresses in IPX and IP Host-
Only environments is addressed through the HP router OS version
described below. However, for XNS and DECnet environments, a satisfac-
tory solution is not available from any vendor at this time.
Note Operating problems associated with duplicate MAC addresses are likely to
occur in VLAN environments where XNS and DECnet are used. For this
reason, using VLANs in XNS and DECnet environments is not currently
supported.
■ Before you can delete a VLAN, you must first remove all of its unmeshed
ports from the VLAN and re-assign all ports in the VLAN to another VLAN.