A wireless local access network (WLAN) is an internal network consisting of wirelessly connected equipment. An ad hoc network is a network where computers talk to each other directly without using any form of access point. So an ad hoc WLAN is a system where multiple wireless devices are able to talk to each other without using any form of central routing system. An ad hoc WLAN is common in places where computer users need to share information, but cannot or will not connect to a wireless network.
In a standard network, information comes in from the outside through a single source. This information goes to a router; it then determines which connected computer requires the information and sends it off. Devices connected to the internal network are able to connect to each other freely—no additional connection protocols are required. This system relies on a central access point, in this case a router, to divide the information and determine communication priority.
Normally, when devices are not connected to the same network, they have difficulty talking to one another. In most cases, additional communication programs or login information are required to make the connection between the two systems, if one can be made at all. Many computers have safety procedures in place to prevent other systems from connecting without direct user intervention.
An ad hoc network bypasses both standard routing and common communication difficulties by allowing the machines to talk to one another directly. Two or more machines are connected directly to one another with network cable, or in the case of an ad hoc WLAN, a wireless signal. Any communication protocols are determined at initial connection, and then the machines behave as though they were on a standard network.
These systems were common before the advent of the Internet. Small offices would have connected computers, allowing workers to communicate or transfer files from one machine to another. Larger offices often used central servers and switching, taking them from ad hoc networks to standard ones. Home computers were connected together to play offline multiplayer games and share information.
With the ubiquitous nature of the Internet, such networks aren’t as necessary as before. Offices require connections to the Internet and, therefore, use a central access point and remove the need for ad hoc connections. Single computers connected to the Internet have access to other computers and information without direct wiring.
The main purpose of a typical ad hoc WLAN is privacy. In an ad hoc WLAN situation, a user needs to directly connect a computer to another using a special wireless protocol. Other connections need to do the same thing, making it nearly impossible for a device to connect without alerting someone of its presence. In some cases, two computers will both connect to a third, allowing communication between them, but giving no indication of who they are.