Port-Based VLANs

Port-based VLANs are configured by associating switch ports to VLANs in two ways: first, by manipulating the port VLAN ID (PVID); and second, by adding the port itself to the egress list of the VLAN corresponding to the PVID. Any traffic received by a port is associated to the VLAN identified by the port's PVID. By virtue of this association, this traffic may egress the switch only on those ports listed on the VLAN's egress list. For example, given a VLAN named “Marketing,” with an ID value of 6, by changing the PVID values of ports 1 through 3 to 6, and adding those ports to the egress list of the VLAN, we effectively restrict the broadcast domain of Marketing to those three ports. If a broadcast frame is received on port 1, it will be transmitted out ports 2 and 3 only. In this sense, VLAN membership is determined by the location of traffic ingress, and from the perspective of the access layer—where users are most commonly located—egress is generally untagged.