Six Required Components of a LAN

As computer networking has become less expensive and easier to implement, many businesses have implemented Local Area Networks to share resources and improve company communications. There are a number of components that make up a LAN, and understanding them can help reduce your network implementation costs, whether you outsource it or do it yourself.

Network cables connect all of the devices on your network to a central point, typically a switch or a hub. Most networks use Unshielded Twisted Pair wiring denoted with a category, often referred to as Cat-x, where "x" is a number representing the grade of the wiring. The higher the number, the higher the wire grade, which translates to higher potential network speed. Fiber optic cable is used in cases where very high bandwidth is needed and where there is a lot of electromagnetic interference. Fiber optic cable is much more expensive than UTP wiring.

Each networked device contains a Network Interface Card. The NIC may be a separate board installed into a computer's slot, or it may be built into the motherboard. Either way, the NIC is the bridge between the computer and the network, and is a gatekeeper of sorts, because it decides whether to process a data packet or not, either passing it on to the computers processor or discarding it based on the destination address in the packet. The NIC also takes information from the processor, formats it for transmission and puts it on the wire.

A hub is the central wiring connector on a LAN, where all of the network cables come together. Each cable plugs into a port on the hub. The hub accepts incoming data packets from devices on the network and transmits them to all other computers attached to the hub. Each device NIC receives each packet and makes its process or discard decision.

A switch is like a hub in that it is a central point for connecting network cables; however, a switch is able to receive a packet and transmit it to only the destination computer. It does this by building a table of which computer is on which of its ports. This reduces network traffic significantly, especially on a network of more than 10 computers. It is not unusual to find both hubs and switches on the same LAN.

Network routers are essentially very smart switches because they know about other LANs, while switches only know about the network they are on. Routers connect LANs together, sometimes across long distances, creating Wide Area Networks, or WANs. Routers are also used to provide security on LANs by routing network traffic between LAN segments.

All of the network components except the cabling have software that makes them work. Network software is written to a set of standards that define the TCP/IP protocol suite. The standard defines layers of software and how they talk with each other. Using the same set of rules allows networking equipment from different vendors to work together, allowing you to take advantage of the best equipment in each category.