4.2 VLAN Types
4.2.3 Local VLANs

End-to-end VLANs allow devices to be grouped based upon resource usage. This includes such parameters as server usage, project teams, and departments. The goal of end-to-end VLANs is to maintain 80 percent of the traffic on the local VLAN.

As many corporate networks have moved to centralize their resources, end-to-end VLANs became more difficult to maintain. Users are required to use many different resources, many of which are no longer in their VLAN. Because of this shift in placement and usage of resources, VLANs are now more frequently being created around geographic boundaries rather than commonality boundaries.

This geographic location can be as large as an entire building or as small as a single switch inside a wiring closet. In a geographic VLAN structure, it is typical to find the new 20/80 rule in effect with 80 percent of the traffic remote to the user and 20 percent of the traffic local to the user. Although this topology means that the user must cross a Layer 3 device in order to reach 80 percent of the resources, this design allows the network to provide for a deterministic, consistent method of accessing resources.

Geographic VLANs are also considerably easier to manage and conceptualize than VLANs that span different geographic areas.