Planet WGD-800 User Manual page 47

802.1Q VLAN Configuration
There are up to 256 configurable VLAN groups. By default when 802.1Q is enabled, all ports on the switch belong
to default VLAN (VID 1). The default VLAN cannot be deleted.
Understand nomenclature of the Switch
Tagging and Untagging
Every port on an 802.1Q compliant switch can be configured as tagging or untagging.
Tagging: Ports with tagging enabled will put the VID number, priority and other VLAN information into the
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header of all packets that flow into those ports. If a packet has previously been tagged, the port will not alter
the packet, thus keeping the VLAN information intact. The VLAN information in the tag can then be used by
other 802.1Q compliant devices on the network to make packet-forwarding decisions.
Untagging: Ports with untagging enabled will strip the 802.1Q tag from all packets that flow into those ports.
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If the packet doesn't have an 802.1Q VLAN tag, the port will not alter the packet. Thus, all packets received
by and forwarded by an untagging port will have no 802.1Q VLAN information. (Remember that the PVID is
only used internally within the Switch). Untagging is used to send packets from an 802.1Q-compliant
network device to a non-compliant network device.
Frame Income
Frame Leave
Leave port is tagged
Leave port is untagged
Here pay attention to the explainion of "Access", "Always Untag"and "Trunk".
Access: Ports will strip the 802.1Q tag from all packets that out of those ports. If the packet doesn't have an
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802.1Q VLAN tag, the port will not alter the packet. Thus, all packets received by and forwarded by an
untagging port will have no 802.1Q VLAN information. Untagging is used to send packets from an
802.1Q-compliant network device to a non-compliant network device.
Ports with "Access" mode belong to a single untagged VLAN.
Trunk: Ports with tagging enabled will put the VID number, priority and other VLAN information into the
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header of all packets that out of those ports. If a packet has previously been tagged, the port will not alter the
packet, thus keeping the VLAN information intact. The VLAN information in the tag can then be used by
other 802.1Q compliant devices on the network to make packet forwarding decisions.
Always Untag: The port belongs to VLANs, and each VLAN is user-defined as tagged or untagged (full
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802.1Q mode). Ports will strip the 802.1Q tag from all packets that out of those ports.
Income Frame is tagged
Frame remains tagged
Tag is removed
Income Frame is untagged
Tag is inserted
Frame remain untagged