Computer or communication networks can be broadly classified based on whether they are physically connected or are intermittently connected using radio signals. Computer networks that are connected by a piece of wiring, such as a coaxial cable are known as

wired networks

. Wireless networks use radio signals as their physical layer. The ability to connect two or more computers without the need of cumbersome wiring and the flexibility to adapt to mobile environments have been fueling the widespread acceptance and popularity of wireless networks. For an overview of computer networks refer to (Stallings 2002, Chao and Guo 2002, Walrand and Varaiya 1996, Tanenbaum 1996).