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9033645-01 Virtual LANs (VLANs) 93
Forwarding Tagged/Untagged Frames
Ports can be assigned to multiple tagged or untagged 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 “Port
Assignment VLAN Configuration” on page 53). .
Figure B-1. Multi-Switch VLAN Configuration
Automatic VLAN Registration
GVRP defines a system whereby the switch can automatically learn the
VLANs each endstation should be assigned to. If an endstation (or its
network adapter) supports the IEEE 802.1Q VLAN standard, it can be
configured to broadcast a message to your network indicating the VLAN
groups it wants to join. When this switch receives these messages, it will
automatically place the receiving port in the specified VLANs, and then
forward the message to all other ports. When the message arrives at
another switch that supports GVRP, it will also place the receiving port in
the specified VLANs, and pass the message on to all other ports. VLAN
requirements are propagated in this way throughout the network. This
allows GVRP-compliant devices to be automatically configured for VLAN
groups based solely on endstation requests.