By Humayun Bakht
Wireless, or single-hop networks, until recently were based on a fixed structure, basically network nodes communicating to fixed infrastructure. Mobile ad-hoc networking offers multi-hop communication, in effect network nodes communicating via other nodes.
In situations where networks are constructed and destructed in ad-hoc manner, mobile ad-hoc networking is an excellent choice. The idea of mobile ad-hoc or packet radio networks has been under development since 1970s. Since the mid-90s, when the definition of standards such as IEEE802.11 (what we think of as WiFi or just 802.11) helped cause commercial wireless technology to emerge, mobile ad-hoc networking has been identified as a challenging evolution in wireless technology.
In this article, I'll highlight some of the characteristics of a mobile ad-hoc network. This article will be helpful for both technical and non technical readers in gaining a wider understanding of mobile ad-hoc networks and their characteristics.
A mobile ad-hoc network is a collection of mobile devices equipped with a transmitter and receiver, connected in the absence of fixed infrastructure. Mobile ad-hoc network is defined with characteristics such as purpose-specific, autonomous and dynamic. In comparison with fixed wireless networks, there is no master slave relationship that exists in a mobile ad-hoc network. Nodes rely on each other to established communication, thus each node acts as a router. Therefore, in a mobile ad-hoc network, a packet can travel from a source to a destination either directly, or through some set of intermediate packet forwarding nodes.
The control and management of mobile ad-hoc network is distributed among the participating nodes. Each node is responsible to forward packet to other nodes in the networks. The nodes are also collaborate themselves to implement network routine functions such as security. Nodes in mobile ad-hoc network are highly mobile which causes network topology to change rapidly and unpredictably, as you can see in the graphic provided in Figure A.
FIGURE A
The mobile ad-hoc network on the left constructs itself as needed. (click for larger image)
Moreover the connectivity among the hosts varies with time. In most cases, mobile ad-hoc networks operate on low power devices. Normally these devices have low CPU process capability and small memory sizes, thus affect the capability of the mobile ad-hoc network to reach other devices.
It has been clear that routing in mobile ad-hoc network, meaning transferring packets from source to destination, is different than traditional routing in a fixed network. Routing in mobile ad-hoc networking depends on many factors which includes topology, selection of routers, initiation of request and available bandwidth.
