Frequently Asked Questions (FAQ)

1:

Are VLANs standardized?

A1:

Yes, with the caveat that the switch vendors do deploy proprietary implementations. Before VLANs were standardized by the IEEE, each vendor developed its own unique and proprietary VLAN solution and product. Switches from one vendor, implementing the vendor's proprietary solution, will not necessarily interoperate with VLANs from other vendors. However, the IEEE has defined the 802.1q standard for VLAN implementations to ensure the interoperability of VLAN implementations between switches and NICs from different vendors. A second IEEE specification, 802.1p, defines the use of priority bits, which are part of the explicit VLAN tag as defined in 802.1q. Two different VLAN models are specified in the 802.1q specification: the shared model and the independent model. Geographically diverse sites can share VLAN resources across a WAN. Workstations within the same VLAN can communicate with each other across the WAN through the network (edge) routers attached to each VLAN switch.