Hi,
A good example of an optical ad-hoc network is the infrared system IRDA, used on PDA's and laptops. someone wanting to print for instance, just points their PDA at the printer and prints.
The IEEE 802.11 standard
The IEEE 802.11communications standard defines the protocol for two types of networks; Ad-hoc and client/server.
The Ad-hoc network is a simple network where communications are established between multiple stations in a given coverage area without the use of an access point or server. The 802.11- standard specifies the etiquette that each station must observe so that all units have fair access to the wireless media. It provides methods for arbitrating requests to use the media to ensure that throughput is maximized for all of the users in the base service set.
The client/server network uses an access point that controls the allocation of transmit time for all stations and allows mobile stations to roam from cell to cell. The access point is used to handle traffic from the mobile radio to the wired or wireless backbone of the client/server network. This arrangement allows for point coordination of all the stations in the basic service area and ensures proper handling of the data traffic. The access point routes data between the stations and other wireless stations or to and from the network server.
Typically, WLANs (i.e. wireless LANs) controlled by a central access point will provide better throughput performance than ad-hoc networks.
So ad hoc network is a peer to peer network without a server or a access point and is set up on the fly.
Can a blue tooth network be called an ad hoc? Because when multiple blue tooth are present in range, one assumes a masetr role and others are slaves. (So I read somewhere... not 100% sure.)