D-Link DES-3326SR User Manual page 63

DES-3326SR Layer 3 Fast Ethernet Switch User's Guide
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Egress rules – determines if the packet must be sent
tagged or untagged.
Figure 5-6. IEEE 802.1Q Packet Forwarding
802.1Q VLAN Tags
The figure below shows the 802.1Q VLAN tag. There are four
additional octets inserted after the source MAC address. Their
presence is indicated by a value of 0x8100 in the EtherType
field. When a packet's EtherType field is equal to 0x8100, the
packet carries the IEEE 802.1Q/802.1p tag.
contained in the following two octets and consists of 3 bits or
user priority, 1 bit of Canonical Format Identifier (CFI – used
for encapsulating Token Ring packets so they can be carried
across Ethernet backbones) and 12 bits of VLAN ID (VID). The
3 bits of user priority are used by 802.1p. The VID is the VLAN
The tag is
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