Computer networking

A computer network is a set of devices linked so they can exchange data and share resources. Networks are commonly classified by their reach: a local area network (LAN) covers a single building or campus, while a wide area network (WAN) connects sites across cities or countries, with the public internet being the largest example. The way devices are arranged is the physical topology, with common patterns including the bus, ring, and star, each affecting how cabling is laid out and how a single fault propagates.

Within a LAN, switches forward frames only to the port leading to their destination, improving efficiency over older shared media, while routers connect different networks and choose paths for traffic between them. Data moves according to layered protocols, most importantly the TCP/IP suite, where IP handles addressing and routing and TCP provides reliable, ordered delivery. Serial standards such as RS-232 and RS-485 and interfaces like USB define the electrical and signalling rules for many point-to-point links.

Several practical concepts govern how data is carried. Communicating equipment is often split into data terminal equipment (DTE) and data communication equipment (DCE), the classic example being a computer and its modem. Baud rate measures signalling events per second, which is not always the same as the bit rate when each signal carries more than one bit. Flow control prevents a fast sender from overwhelming a slow receiver, and error-handling techniques such as the cyclic redundancy check, together with forward error correction through encoding and decoding, keep transmitted data reliable.

Frequently asked questions

What is the difference between a switch and a router?

A switch forwards frames between devices on the same local network, while a router connects separate networks and decides how to route traffic between them, for instance from a LAN to the internet.

Are baud rate and bit rate the same?

Not necessarily. Baud rate counts signalling events per second; when a single signalling event encodes several bits, the bit rate is higher than the baud rate.

What do DTE and DCE mean?

DTE is data terminal equipment such as a computer, and DCE is data communication equipment such as a modem that conditions the signal for the transmission line between them.