Allied Telesis AT 8000/8POE - Manual (Page 116)

Chapter 9: Virtual LANs and GVRP
116 Section I: Using the Menus Interface
Outgoing Frames
Frames being transmitted from the switch retain their VLAN tag
information in the frame header if the frame’s tag does not match the PVID
of the port (a tagged member of that VLAN). These frames are untagged
after transmission from the switch.
The VLAN tag information in the header of the frame is stripped from the
frame’s header if the tag matches the PVID of the port (an untagged
member of the VLAN). These frames are untagged after transmission from
the switch.
Guidelines for
Creating a VLAN
The following are guidelines for creating a VLAN.
 Each VLAN must be assigned a unique VID. If a
particular VLAN spans multiples switches, each part of
the VLAN on the different switches should be assigned
the same VID.
 A port can be an untagged member of only one VLAN
at a time.
 Each port must be assigned a PVID (the default is 1).
This value must match one of the VIDs assigned to the
port. If you need to change the PVID value, you must
configure it on a port after you assign a port to a VLAN.
For instructions, refer to “Configuring the Port PVID” on
page 124.
 A VLAN that spans multiple switches requires a port on
each switch where the VLAN is located to function as
an interconnection between the switches where the
various parts of the VLAN reside.
 This port may be defined as an untagged member of a
VLAN where the port is connected to another switch
via another untagged port member of the VLAN. This
means that all traffic on this inter-switch port contains
traffic for that VLAN only.
 Another scenario is where the port could be an
untagged member of one VLAN and a tagged member
of one or more VLANs. The port would then be
connected to another switch via a port with the same
VLAN membership. This means that the traffic on this
inter-switch port is for any or all of the VLANs of which
the port is a member.
 If there are end nodes in different VLANs that need to
communicate with each other, a router or Layer 3
switch is required to interconnect the VLANs.
 The switch can support up to a total of 255 VLANs.