A computer network is a system for communication among two or more computers.
Computer networks may be categorized with respect to range:

personal area network (PAN)

wireless PAN

local area network (LAN)

wireless LAN

metropolitan area network (MAN)

wide area network (WAN)

(Tiny area network (TAN)

Computer network applications may be categorized with respect to the functional relationships between components:

client-server

multitier architecture

peer-to-peer

Computer networks [...]