Six Basic Computer Network Components
Computer networking has become much easier over the years, and it is now possible to set up your own computer network in your home with just a little bit of help. There are multiple components that go into computer networks, but not all of these are needed in every type of network. An understanding of the various components that are available can help you design the right network for your home or business environment.
Every device on the network has to have a network interface of some design. The network interface is sometimes referred to as a NIC (network interface card) and may be integrated into the computer's motherboard or may be a separate card. The NIC is the component that takes information from the computer and sends it out onto the network wire, or into the air in the case of a wireless network.
When you connect multiple computers on a network, they all plug into a central device called a hub. The hub has the job of moving the network signal from one wire to another. In the case of a basic hub, the signal from one computer is sent to all other computers on the hub, and each NIC decides whether to pass the information to the computer or just drop it if it is not the intended recipient.
Switches are really smart hubs in that they are able to build tables that keep up with which computer is on which switch port. With this intelligence, a switch does not transmit all information to all other computers on the switch, just to the destination computer. Switching technology helps to reduce congestion on a network and should be used for networks of 10 or more computers.
Routers are really smart switches in that they are aware of other networks, while hubs and switches are only aware of the network they facilitate. Routers are used to connect one local area network (LAN) to another, many times across long distances via commercial data carriers. Another way routers are smart is they can dynamically update their routing information, detecting when one route to a network is down, and checking to see if another route is available.
Of course, none of these networking devices work well unless they are connected to each other, and that is done with various media. The most ubiquitous media is commonly called Ethernet cabling, which is actually one of several categories of unshielded twisted pair (UTP) wiring. The higher the cable rating -- i.e., Cat5, Cat6, Cat7 -- the higher the bandwidth the cable can support. In addition, there is fiber optic cable, which is more expensive and uses laser or LED light rather than electrical pulses. Wireless has become popular in homes due to the ease and low expense of setting up a network. The "media" for a wireless network is the air, through which the wireless NICs transmit radio signals that carry information.
Software is the intelligence that causes all of the components to function together. The most popular network software today uses what is known as the TCP/IP protocol suite, or stack. The suite is constructed from actual layers of software, where each has its own function. While the seven-layer OSI model -- Physical, Data Link, Network, Transport, Session, Presentation and Application -- is the starting point for network stacks, the Internet model has four layers -- Link, Internet, Transport and Application -- that combine several of the seven OSI layers into the other layers. These layers play by the same set of rules so heterogeneous computer systems can communicate with each other, regardless of differences in hardware or operating systems.