Allied Telesis AT-S63 - Manual (Page 315)

AT-S63 Management Software Features Guide
Section VI: Virtual LANs 315
VLAN Hierarchy
The switch’s management software employs a VLAN hierarchy when
handling untagged packets that arrive on a port that is an egress port of a
MAC address-based VLAN as well as an untagged port of a port-based
VLAN. (A port can be a member of both types of VLANs at the same time.)
The rule is that a MAC address-based VLAN takes precedence over that
of a port-based VLAN.
When an untagged packet arrives on a port, the switch first compares the
source MAC address of the packet against the MAC addresses of all the
MAC address-based VLANs on the device. If there is a match, the switch
considers the packet as a member of the corresponding MAC address-
based VLAN and not the port-based VLAN, and forwards it out the egress
ports defined for the corresponding MAC address-based VLAN.
If there is no match, the switch considers the packet as a member of the
port-based VLAN and forwards the packet according to the PVID assigned
to the port. For an explanation of a PVID, refer to “Port-based VLAN
Overview” on page 273.