The switched network retains the performance of the LAN segment, while the logical arrangement controls broadcast traffic and creates secure communities of interest. The traffic patterns show workflow rather than a network topology. Address administration is simplified because there are fewer subnetworks and because endstations can move between segments in the same VLAN without address configuration. A VLAN can be defined by protocol group or by application. Creating initial groups based on endstations that share common protocols may be an excellent way to begin the definition of VLANs.
Application domains are a bit more difficult to define.
While users may run multiple protocol stacks or merge to a new protocol environment, the same applications are likely to be used over again. While LAN switching can improve network performance and relieve backbone congestion, it is ultimately limited by the speed of attached LANs. ATM uses short fixed-length cells to keep switch latency to a minimum to make cell processing simple and deterministic, delivering highly scalable performance. Like a LAN switch, this device interfaces directly with traditional LANs and is transparent to existing applications and operating systems. Like an ATM switch, it sends traffic across the backbone as cells.