Internet technology explained

The internet is the global system of interconnected networks over which a wide range of services operate. Underneath every service lies the TCP/IP protocol suite, which addresses devices with IP addresses and reliably delivers data between them. Because plain numerical addresses are impractical for people, the Domain Name System maps memorable domain names to those addresses, and uniform resource locators identify the exact resource a browser or program should fetch.

The most visible service is the World Wide Web. Web servers store and deliver web pages, responding to requests from browsers, which then display the returned content. Pages may be written directly in markup or generated on the fly using APIs, CGI scripts, and data formats such as XML, while cookies let a site remember information between visits. Alongside the web, email carries messages between users, and older systems such as Usenet host discussion newsgroups, each running over the same underlying network.

Performance and access depend on the connection. Bandwidth describes how much data a link can carry per unit of time, and broadband technologies such as VDSL and other DSL variants, cable, and fibre provide the high-capacity connections that modern services need. Servers, port numbers, and protocols coordinate so that many services share the same infrastructure: a single machine can host a website, handle email, and answer name lookups at once. Understanding these pieces — addressing, servers, services, and the links between them — gives a clear picture of how the internet functions.

Frequently asked questions

What is a web server?

A web server is a computer and program that stores web pages and other resources and sends them to browsers that request them, forming the backbone of the World Wide Web.

What does bandwidth mean?

Bandwidth is the amount of data a network connection can carry in a given time; higher bandwidth, as offered by broadband links, allows faster transfers and richer services.

What is Usenet?

Usenet is an early internet system of discussion newsgroups in which users post and read messages on topics of interest, predating and existing alongside the web.