Allied Telesis AT-S60 - Manual (Page 406)

Chapter 18: Virtual LANs
Section IV: VLANs 406
For example, assume that you were creating a port-based VLAN on a
switch and you had assigned the VLAN the VID a value of 5.
Consequently, the PVID for each port in the VLAN would need to be
assigned the value of 5.
Some switches and switch management programs require that you
assign the PVID value for each port manually. However, the AT-S60
management software performs this task automatically. The software
automatically assigns a PVID to a port, making it identical to the VID of
the VLAN to which the port is a member.
General Rules
for Creating a
Port-based
VLAN
Below is a summary of the general rules to observe when creating a port-
based VLAN.
❑ Each port-based VLAN must be assigned a unique VID. If a
particular VLAN spans multiples switches, each part of the VLAN
on the different switches must be assigned the same VID.
❑ A port can be an untagged member of only one port-based VLAN
at a time.
❑ The ports on an AT-8400 line card can belong to the same VLAN or
to different VLANs.
❑ Each port must have a PVID. This value must be the same for all
ports in a port-based VLAN and must match a VLAN’s VID. This
value is assigned automatically by the AT-S60 management
software.
❑ A port-based VLAN that spans multiple switches requires a
dedicated port on each switch to function as an interconnection
between the switches where the various parts of the VLAN reside.
❑ If end nodes in different VLANs need to communicate with each
other, a router or Layer 3 switch is required to interconnect the
VLANs.
❑ An AT-8400 Series switch can support up to 256 VLANs.
Drawbacks of
Port-based
VLANs
There are several drawbacks to port-based VLANs:
❑ It is not easy to share network resources, such as servers and
printers, across multiple VLANs. A router or Layer 3 switch must be
added to the network to provide a means for interconnecting the
port-based VLANs.