Apache Systems 

Virtual LANs (VLANs) can help IT managers adapt to these changes more easily and effectively, while increasing overall network performance. By offering a highly flexible means of segmenting a corporate network, VLANs reduce the performance bottlenecks that occur when traditional backbone routers can't meet the demands of fast, switched networks.

A VLAN is a group of PCs, servers and other network resources that behave as if they were connected to a single, network segment — even though they may not be. For example, all marketing personnel may be spread throughout a building. Yet if they are all assigned to a single VLAN, they can share resources and bandwidth as if they were connected to the same segment (see Figure 1). The resources of other departments can be invisible to the marketing VLAN members, accessible to all, or accessible only to specified individuals, at the IT manager's discretion.

This logical grouping of network nodes helps free IT managers from the restrictions of their existing network design and cabling infrastructure. It offers a fundamental improvement in the ease with which LANs can be designed, administered and managed. And since VLANs are software-based, they allow the network structure to quickly and easily adapt to the addition, relocation or reorganization of nodes. No longer does each change require a visit to the wiring closet.

Equally important, VLANs help meet performance needs by segmenting the network more effectively. Unlike standard switching, they restrict the dissemination of broadcast as well as node-to-node traffic, so the burden of extraneous traffic is reduced throughout the network. Security can also be improved. Since all packets traveling between VLANs may also pass through a router, standard router-based security measures can be implemented to restrict access as needed.

Despite the advantages of a well-designed VLAN solution, the newness of the technology and the large number of proprietary implementations have created confusion in the marketplace. Some industry pundits have charged that VLANs may eventually become unnecessary as routing becomes faster and high-bandwidth technologies such as Fast Ethernet and Gigabit Ethernet emerge. They also note a slow, industry-wide trend toward protocols that depend less upon broadcast traffic.

These changes may, to some extent, reduce the importance of VLAN solutions in the future, but they won't eliminate many of the key advantages of the technology. And VLANs offer an immediate and cost-effective solution to several very real networking challenges — a solution that can be integrated into existing networks without costly overhauls. The potential benefits should not be ignored.

 John fROM INTELL