10.4 LAN: What Are The Important Issues in Design?

A LAN (local area network) refers to the network that connects the devices in one geographic location, such as a single building. A LAN is based on any physical network technology designed to span distances up to a few thousand meters, although the "local" in LAN can sometimes be extended to include all the devices in a campus environment. As a general rule, a LAN's boundary is telecommunication facilities (T-1 lines, ISDN, etc.). These facilities are generally considered to be part of the WAN (wide area network).

Designing a LAN is like designing a house. It is dependent on needs, plans for future growth, and changes of use, and the definition of a good design can vary with changes and trends in the marketplace. The goals of a good LAN design should include the following:

• Maximizing the efficiency of network traffic: Moving the data from Point A to Point B as fast as possible.
• Reliability: A LAN is one of those things that no one notices until it fails to function.
• Manageability: So that you can see trends of growth and traffic patterns, as well as identify bottlenecks and problem areas.
• Flexibility: To be able to adapt to changing environment needs (not the least of which is growth), as well as the introduction of new technologies.

Of course, there is no black and white, right or wrong, when it comes to LAN designs. Like designing a house,...