How does a VLAN work

IEEE 802.1Q is the current Network standard for Virtual Local Area Networks (VLANs). Each Ethernet Frame has a VLAN ID from 1 to 4095. The most common VLAN is port-based VLAN where any traffic coming into the port automatically gets tagged with the VLAN ID that is placed on that port. These tags are added to the Ehternet frame between the source MAC address and the Ethertype so the VLAN ID is maintained through the whole Network. If more than VLAN is needed to pass through a switch port, it is set to Trunk mode otherwise for only one VLAN it is set to Edge mode. One VLAN is always set to Native ID or Port VLAN ID (PVID) to capture all non-tagged data.

IEEE802.1P is a standard that provides Class of Service operations to Layer 2 Networks (VLAN Priority). This Priority Control Point (PCP) value is part of the VLAN tag and ensures that frames with higher priority are processed before others.

Narrated by iS5 Communications’ Field Application Engineer Dominic Iadonisi. .