Allied Telesis AT-S62 - Manual (Page 578)

Chapter 27: Multiple VLAN Modes
Section V: Virtual LANs 578
Non-802.1Q
Compliant
Multiple VLAN
Mode
Unlike the 802.1Q-compliant VLAN mode, which isolates port traffic by
placing each port in a separate VLAN, this mode forms one VLAN with a
VID of 1 that encompasses all ports. Traffic isolation is established
through port mapping. The result, however, is the same. Ports are
permitted to forward traffic only to the designated uplink port and to no
other port, even when they receive a broadcast packet.
With this mode the uplink port is untagged. You would want to use this
mode when the device connected to the uplink port is not IEEE 802.1Q
compatible, meaning that the device cannot handle tagged packets.
Note
When the uplink port receives a packet with a destination MAC
address that is not in the MAC address table, the port will broadcast
the packet to all switch ports. This can result in ports receiving
packets that are not intended for them.
It should also be noted that a switch operating in this mode can be
remotely managed through any port on the switch, not just the
uplink port.