Example of Networked 802.1Q-compliant devices with multiple VLANs on some ports

In the following network, switches X and Y and servers S1, S2, and the AppleTalk server are 802.1Q-compliant. (Server S3 could also be 802.1Q-compliant, but it makes no difference for this example.) This network includes both protocol-based (AppleTalk) VLANs and port-based VLANs.

The VLANs assigned to ports X4 - X6 and Y2 - Y5 can all be untagged because there is only one VLAN assigned per port.
Port X1 has two AppleTalk VLANs assigned, which means that one VLAN assigned to this port can be untagged and the other must be tagged.
Ports X2 and Y1 have two port-based VLANs assigned, so one can be untagged and the other must be tagged on both ports.
Ports X3 and Y6 have two port-based VLANs and one protocol-based VLAN assigned. Thus, one port-based VLAN assigned to this port can be untagged and the other must be tagged. Also, since these two ports share the same link, their VLAN configurations must match.

In the table, "No" means that the port is not a member of that VLAN. For example, port X3 is not a member of the Red VLAN and does not carry Red VLAN traffic. Also, if GVRP were enabled (port-based only), Auto would appear instead of No.

Switch X					Switch Y
Port	AT-1 VLAN	AT-2 VLAN	Red VLAN	Green VLAN	Port	AT-1 VLAN	AT-2 VLAN	Red VLAN	Green VLAN
X1	Untagged	Tagged	No	No	Y1	No	No	Untagged	Tagged
X2	No	No	Untagged	Tagged	Y2	No	No	No	Untagged
X3	No	Untagged	Untagged	Tagged	Y3	No	Untagged	No	No
X4	No	No	No	Untagged	Y4	No	No	No	Untagged
X5	No	No	Untagged	No	Y5	No	No	Untagged	No
X6	Untagged	No	No	No	Y6	No	Untagged	Untagged	Tagged

NOTE:

VLAN configurations on ports connected by the same link must match. Because ports X2 and Y5 are opposite ends of the same point-to-point connection, both ports must have the same VLAN configuration, configuring the Red VLAN as "Untagged" and the Green VLAN as "Tagged.”