A network is a way to connect computers for communication, information exchange, and resource sharing. The four most important benefits of networking are simultaneous access to programs and data, peripheral sharing, streamlined communications, and easier backups. E-mail, videoconferencing, and teleconferencing are examples of the personal communications that can be conducted over a network or the Internet.
Networks can be categorized in different ways, such as by geography (how much terrain they cover) or by the use or absence of a central server.
A local area network (LAN) consists of computers that are relatively near one another. A LAN can have a few PCs or hundreds of them in a single building or in several buildings. On a network, data is broken into small groups called packets before being transmitted from one computer to another. A packet is a data segment that includes a header, payload, and control elements that are transmitted together. The receiving computer reconstructs
the packet into the original structure.
The payload is the part of the packet that contains the actual data being sent. The header contains information about the type of data in the payload, the source and destination of the data, and a sequence number so that data from multiple packets can be reassembled at the receiving computer in the proper order. Each LAN is governed by a protocol, which is a set of rules and formats for sending and receiving data. TCP/IP, IPX/SPX, and NetBEUI are examples of network protocols.
LANs can be connected by a bridge or router to create a much larger network that covers a larger geographic area. To connect LANs, a gateway may be required to enable them to share data in a way that the different LANs can understand.
A wide area network (WAN) is the result of connecting LANs through public utilities.
Many networks are built around a central server. The PCs that connect to the server are called nodes. In a file server network, each node has access to the files on the server but not necessarily to files on other nodes. In a client/server network, nodes and the server share the storage and processing workload.
A peer-to-peer network is a small network that usually does not include a central server. In a peer-to-peer network, users can share files and resources on all the network’s nodes.