Specifications

Switching 8-21
Software Release 2.7.3
C613-03098-00 REV A
Summary of VLAN Tagging Rules
When designing a VLAN and adding ports to VLANs, consider the following
rules:
• Except for the mirror port, each port must belong to at least one static
VLAN. By default, a port is an untagged member of the default VLAN.
• A port can be untagged for zero or one VLAN. A port that is untagged
for a VLAN transmits frames destined for that VLAN without a VLAN
tag in the Ethernet frame.
• A port can be tagged for zero or more VLANs. A port that is tagged for
a VLAN transmits frames destined for that VLAN with a VLAN tag,
including the numerical VLAN Identifier of the VLAN.
• A port cannot be untagged and tagged for the same VLAN.
• The mirror port, if present, is not a member of any VLAN.
VLAN Interaction with Trunk Groups
All the ports in a trunk group must have the same VLAN configuration. They
must belong to the same VLANs and have the same tagging status; and they
must be operated on as a group.
Static and Dynamic VLANs
All VLANs created by the user on the command line are static VLANs. The
default VLAN is also a static VLAN. A port must belong to at least one static
VLAN.
Dynamic VLANs are created by GVRP, a GARP application whose purpose is
to propagate VLAN information between VLAN aware switches (see the
Generic Attribute Registration Protocol (GARP) chapter). These dynamic VLANs
are entitled gvrpxxx, where xxx is the VLAN’s VLAN Identifier. Dynamic
VLANs are created only when GVRP is enabled on the switch. GVRP is
disabled by default.
All static VLANs except for the default VLAN can be destroyed by the user.
Dynamic VLANs cannot be directly destroyed by the user, but may be
destroyed according to the operations of GVRP by using the reset garp
command on page 9-15 of Chapter 9, Generic Attribute Registration Protocol
(GARP) or by disabling the GVRP instance.
A user can add, delete, or modify ports for a static VLAN, but not for a
dynamic VLAN. Dynamic VLANs created by GVRP include only tagged ports.