Most of you have heard the term "network," but do you really know what a network is? Well, a network is a group of two or more computers that are connected with each other. The purpose of networks is to let computers communicate with each other and to share information and data. With networks, multiple computers can access the same files, the same printer, and even the same modem!
Network Classification:
Networks are generally classified by three properties: topology, architecture, and protocol.
Topology, also called network configuration, is the geometric arrangement of the network. The three most common topologies are bus, star, and ring networks.
In a bus topology, every single computer in the network is connected to a single communication cable. Because the beginning and end of this network do not connect (the cable is merely a straight line, with computers connected to it at random intervals), a terminator is placed at each end. Any computer on this network can communicate with another computer of their choice. However, if two computers send data at the same time, then there is a collision. If a collision should occur, then the two computers attempting to send data will wait for a random amount of time, and then they will try to send the information again. Bus topologies are commonly used in offices where computers are spread out throughout the building.
In a star topology, all the computers in the network are connected to a single hub. This topology is inconvenient because all of the information and data has to pass through the hub before it can be transferred to its destination.
Finally, there is the ring topology. In a ring topology, the computers are arranged in a sort of circular shape. Each computer is attached to two others, and all the cables connect to form a circular shape.
2. Architecture:
There are two major types of network architecture: peer-to-peer and client-to-server.
Peer-to-peer networking allows two or more computers to pool their resources together and to share whatever data and information they wish. For example, devices like printers, CD-ROMS, and disk drives can all be shared by the computers! In essence, the computers in peer-to-peer networks act as both clients and servers. They can provide information to the other computers in the network, just like a server does, or they can request information from other computers, like a client. Peer-to-peer networks are only used in homes or businesses with only a few computers. For anything else, it would be impractical. However, an advantage of peer-to-peer networks over client-to-server networks is that they are easy and cheap to set up and manage.
On the other hand, in client-to-server networks, there is one centralized computer, called a file server. This file server acts as a server that provides and stores information for all of the computers that are part of the network. The client computers are separated from each other, and cannot transfer data between themselves. Common uses for client-to-server networks are centrally routed Internet access, e-mail, and file sharing. Client-to-server networks provide for more security than peer-to-peer networks.
3. Protocols:
A protocol is a set of rules used by all of the computers in a certain network to communicate with each other. Now that you know what a protocol is, we will outline a few of the most common ones: IP/TCP, IPX, and NetworkBEUI.
The Internet Protocol (Transmission Control Protocol), or IP, forms the basis of the Internet. Originally developed by the United States' Defense Department, it now spans throughout the whole world!
The IPX protocol is very similar to the Internet Protocol. It, too, was designed to connect large networks. However, IPX is much faster than IP. Unfortunately, IPX doesn't work very well with analog phone lines, which is what most people use to connect to the Internet.
NetworkBEUI is quite different form IP and IPX. It was specially designed for smaller networks. It is extremely fast.
Parts of a Network:
Networks are composed of many different parts. We will now briefly discuss some of the parts of a network:
Of course, in order for a network to work, it needs at least two computers to be connected to it. The Network Interface Card, or NIC, connects the computers to the network. The NIC provides a connection between the networking cable and the computer's internal bus.
Hubs:
Perhaps one of the most important parts of a Network, the hub is the central component of the network. All of the computers and other devices on a network are connected to the hub. This lets them communicate with each other and share data and information. Hubs are not complicated. Rather, they merely pass information along to the various other components of a network.
Bridges and Routers:
Bridges and routers are both used to connect two or more LANs (local-area-networks).
LANs are small networks that usually only include computers in one building.
Bridges and routers can look at information and then transfer it to a whole
different LAN. Routers are slightly more complex than bridges. They can
filter data and then determine the best route for the information when there
is a large network consisting of many LANs.
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