Constructed from communication links and switches, it conveys packets from one node (computer or information appliance) to another. A packet is a collection of data that is conveyed as a unit through the network. A switch routes a packet from one incoming link to the appropriate outgoing link to get it closer to its destination. A local-area network (LAN) is a network designed to be used within a building or narrow geographic reach. An internet is a set of open standards and equipment and software complying with those standards that realizes a network composed of numerous underlying communication and networking technologies, distinguished by its ability to subsume existing and new LAN technologies for network access. Widely used internet standards define protocol layers, including the internet protocol (IP; conveys packets unreliably and without any particular order from one host to another) and the transmission control protocol (TCP; layered on IP, it reliably transports an ordered stream of bytes). The Internet is a large public network utilizing internet technologies; an intranet is a private restricted-access network based on internet technologies; and an extranet extends an intranet to suppliers and partners.
Also called a network externality, an economic characteristic of goods or services for which the value (willingness to pay) to a user or adopter depends on the number of other users or adopters without a compensating payment. The effects may be positive (value increases with adopters, like a network) or negative (value decreases with adopters, like congestion). Network effects may be direct (value of each instance of the good or service is directly affected by other instances) or indirect (value is affected by the quantity of some complementary commodity).
See distributed computing.