Allied Telesis AT-S26 - Manual (Page 98)

Configuring Virtual LANs and Quality of Service
98
Note
Ports can be tagged members of multiple VLANs. This means that
the port can be configured to accept and forward traffic flows from
multiple VLANs (i.e., the port will recognize multiple VIDs).
If the connected device is a legacy device (i.e., a device that does not
support or act upon VLAN tagging), there are addition methods for
handling the frame.
As described in the port-based VLAN section, an untagged incoming
frame needs to have a VID inserted or associated with it so that the
frame can be properly forwarded throughout switch. Consequently,
each port is required to have a VLAN tag associated with it; this port-
based tag is referred to as the Port VLAN ID or PVID. The port PVID
value is inserted into the frame and is used as the frame VID as the frame
is passed through the switching system.
The port PVID assignment enables legacy (non-802.1Q compliant)
devices connected to the switch to take advantage of the VLAN and QoS
capabilities of the switch.
Note
The CPU management port of this switch is a legacy device. It
cannot interpret VLAN tags. The management agent responds only
to communications from devices that are located within the same
VLAN, defined by the management port PVID.