Flexibility in the modern working world brings new challenges for administrators in the design and maintenance of network structures. Office buildings are often dynamic venues where the tenants have shifting demands for space, and where even within a company, the teams are frequently reorganized. However, in both of these cases, each unit needs to have an independent, secured LAN. Achieving this with changes to the hardware is possible either with considerable effort or not at all because, for example, the office building may be equipped with just one central cable infrastructure.
An elegant solution to this task is to use virtual LANs. Even with subsequent changes of departments or companies within the building, the network structure is easily adjusted.
All network users in this example use the central Ethernet, which is, like the connected devices, supervised by a service provider. Company A has three departments on two floors. The Sales department can communicate with the Administration department via VLAN ID 3, the Accounting department with the Administration via VLAN ID 5. The networks of the Accounting department and Sales do not see each other. Company B is also shielded by VLAN ID 11 against all other networks, only the service provider can access all devices for maintenance purposes.
