The Switch User’s Guide
Understand nomenclature of the Switch
Tagging and Untagging
Every port on an 802.1Q compliant switch can be configured as tagging or
untagging.
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Tagging:
Ports with tagging enabled will put the VID number, priority and other
VLAN information into the 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.
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Untagging:
Ports with untagging enabled will strip the 802.1Q tag from all
packets that
flow into those ports
. 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.
Here pay attention to explain of “Access” and “Trunk”.
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Access:
Ports will strip the 802.1Q tag from all packets that
out of those ports.
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. Untagging is used to send packets from an
802.1Q-compliant network device to a non-compliant network device.
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Trunk:
Ports with tagging enabled will put the VID number, priority and other
VLAN information into the 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.
Port VID (PVID)
Set the port VLAN ID that will be assigned to untagged traffic on a given port. This
feature is useful for accommodating devices that you want to participate in the VLAN
but that don’t support tagging. The Switch allows each port to set one PVID, the
range is 1~255, default PVID is 1. The PVID must be the same as the VLAN ID that
the port was defined as belonging to in the VLAN group, or the untagged traffic will
be dropped.
1. First choose 802.1Q VLAN. Click “ok”
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