Allied Telesis AT 8000/8POE - Manual (Page 120)

Chapter 9: Virtual LANs and GVRP
120 Section I: Using the Menus Interface
Ports 1 and 3 on the top switch and ports 2 and 4 on the bottom switch are
assigned a PVID of 2 and are untagged members of only VLAN 2. These
ports are connected to workstations from Sales.
Ports 2 and 4 on the top switch and ports, 3, 6, and 8 on the bottom switch
are assigned a PVID of 3 and are untagged members of VLAN 3 only.
These ports are connected to workstations from Engineering.
Ports 6 and 9 on the top switch and port 5 on the bottom switch are tagged
members of both VLANs 2 and 3. Traffic passed between the switches
and the router consist of tagged packets from both VLANs. These ports
provide a common connection that enables different member ports of the
same VLAN to communicate with each other while maintaining data
separation between VLANs.