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Management Guide
4-3
VLAN Classification
When the switch receives a frame, it classifies the frame in one of two ways:
• If the frame is untagged, the switch assigns the frame to an associated VLAN
(based on the PVID of the receiving port).
• If the frame is tagged, the switch uses the tagged VLAN ID to identify the port
broadcast domain of the frame.
Port Overlapping
Port overlapping can be used to allow access to commonly shared network
resources among different VLAN groups, such as file servers or printers. Note that
if you implement VLANs which do not overlap, but still need to communicate, you
must connect them using a router or Layer 3 switch.
Forwarding Tagged/Untagged Frames
Ports can be assigned to one untagged VLAN and multiple tagged VLANs. Each
port on the switch is therefore capable of passing tagged or untagged frames. To
forward a frame from a VLAN-aware device to a VLAN-unaware device, the switch
first decides where to forward the frame, and then strips off the VLAN tag.
However, to forward a frame from a VLAN-unaware device to a VLAN-aware
device, the switch first decides where to forward the frame, and then inserts a
VLAN tag reflecting this port’s default VID. The default PVID is VLAN 1, but this
can be changed (see page 2-32 or 3-24).