SMC Networks 6924MT, Management Manual

Page: 157 / 178

V
IRTUAL
LAN
S
4-5
frame to the port’s default VLAN if the frame is untagged (determined by
the PVID of the receiving port), or maps it for output to the broadcast
domain associated with the frame’s VLAN tag.
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 can connect them using a Layer 3 switch or a router.
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 for all ports, but this can be changed (see
page 2-62 or page 3-41).