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GS-3012/GS-3012F User’s Guide
257
CHAPTER 34
IEEE 802.1Q Tagged VLAN
Commands
This chapter describes the IEEE 802.1Q Tagged VLAN and associated commands.
34.1 IEEE 802.1Q Tagged VLAN Overview
See the VLAN chapter for more information on VLANs. There are two kinds of tagging:
1 Explicit Tagging
A VLAN identifier is added to the frame header that identifies the source VLAN.
2 Implicit Tagging
The MAC (Media Access Control) number, the port or other information is used to
identify the source of a VLAN frame.
The IEEE 802.1Q Tagged VLAN uses both explicit and implicit tagging.
Whether to tag an outgoing frame depends on the setting of the egress port on a per-LAN, per-
port basis (recall that a port can belong to multiple VLANs). If the tagging on the egress port is
enabled for the VID of a frame, then the frame is transmitted as a tagged frame; otherwise, it is
transmitted as an untagged frame.
34.2 VLAN Databases
A VLAN database stores and organizes VLAN registration information useful for switching
frames to and from a switch. A VLAN database consists of a static entries (Static VLAN or
SVLAN table) and dynamic entries (Dynamic VLAN or DVLAN table).
34.2.1 Static Entries (SVLAN Table)
Static entry registration information is added, modified and removed by administrators only.
34.2.2 Dynamic Entries (DVLAN Table)
Dynamic entries are learned by the switch and cannot be created or updated by administrators.
The switch learns this information by observing what port, source address and VLAN ID (or
VID) is associated with a frame. Entries are added and deleted using GARP VLAN
Registration Protocol (GVRP), where GARP is the Generic Attribute Registration Protocol.