Network Design

In designing a network, it is essential to first determine the scope of the project by asking key questions that will aid in the design and build. Questions such as how many servers and computers will be connected, what is the intended purpose of the network, and how much money is available are basic questions that come immediately to mind. Other questions such as security considerations, and how will the physical architecture of the building affect the design are often ignored but are equally important to the success of the network. Once these questions have been answered, the process of network design can begin. As the design of the network affects both media choices and performance, it is crucial that a design which takes current needs into account, allows room for growth, and provides a proven path for upgradeability is chosen.

In determining the physical layout of the network, the decision of what type of cable to be used is also decided. When broken down to its simplest form, all types of cabling provide a medium across which network information can travel. The most popular types of network cabling in use today are Twisted-pair (TP) in both unshielded (UTP), and shielded (STP) varieties, and Fiber-optic cable. While the use of Coaxial cable has declined in the arena of Local Area Networking (LAN), it is still prominently featured by Cable Television firms, providing both Television, and Internet services.

While the electrical pulses that Twisted-pair wiring carries over a copper medium is different from the pulses of light carried by Fiber-optic over a glass medium, there are cabling characteristics that apply to both. Each cable has a Bandwidth rating, which specifies the amount of data the medium is rated to carry over a set period of time. Usually this is expressed as the number of bits per second, either Mega bits per second (Mbps), or Giga bits per second (Gbps). Category 5 TP cable is rated for speeds up to 100Mbps, operating at 100Mhz, however an enhancement to this, Category 5e cable, is rated for 1Gbps at the same frequency. The latest advancements for TP cabling have improved its speed from 100Mbps to 1Gbps. This speed increase requires the use of a minimum Category 5e rated cable, but is optimized for Category 6 cable, rated at 1Gbps, operating at 200Mhz. Unlike TP cable, Fiber-optic cable does not have Categories. It is rated at speeds up to 1Gbps and is identified by its type of connection, ST for Straight Tip, and SC for Straight Connection are two of the most common. Both TP and Fiber-optic cables are commonly integrated together in a network design. As TP is limited to a maximum distance of 100m, Fiber-optic cable is typically used as a high-speed backbone, extending the network to points farther than 100m.

The cost of cabling and ease of installation is an important factor when deciding what types of cable to run and how long the length of cable will be. By far the easiest and cheapest of the two to install is TP, and can be used to connect all nodes on the network quickly and fairly inexpensively. However, Fiber-optic is expensive to install, requiring specialized