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WIRELESS INFRASTRUCTURE
Routing misbehavior in mobile ad-hoc networks
By Humayun Bakht
Routing is the transfer of data packets from one location to another, and it's one of the fundamental network functions. Network throughput, which is the ratio of data packets sent and received, is directly related to the routing function of any network. In other words, if the routing function is good enough, then we can expect a better output from the network. In today's environment, we see different types of networks. Figure A shows one type of network, a traditional fixed computer network.
FIGURE A
 
Here's what a traditional fixed network looks like. Roll over picture for a larger image.
Another type of network is a wireless network, which you can see in Figure B. Other than a wireless network, which depends on some sort of supporting structure for normal communication operations, mobile ad-hoc networks are short range wireless network provide communication services without the support of any centralized structure.
FIGURE B
 
This figure illustrates how wireless networks work. Roll over picture for a larger image.
Routing in mobile ad-hoc networks is achieved through mobile nodes acting as intermediate nodes. These nodes are responsible for receiving and forwarding data packets from one host to another in the network. The absence of a fixed infrastructure makes routing a challenge in a mobile ad-hoc environment.
There are also several other issues which have an effect on the overall performance of the mobile ad-hoc network. Some of these issues include bandwidth constraints, hidden terminal problems, security and limited battery power of the participating nodes. These issues are somehow interrelated with the overall routing mechanism. In order to gain a better routing solution, it's almost always required to address these issues in conjunction with the routing problem of the mobile ad-hoc network.
Within the traditional routing mechanism, there are also several other issues to consider. For example, a node can become selfish and refuse to forward data packets to other nodes; or the node fails to forward data packets to the destination node. Finally, a node could enter an an inactive state because of a limited power supply. These are some of the issues can result in communication breakdowns and can eventually lead us to an abnormal network environment.
Let's consider when a node refuses to forward data packets to the other nodes. There are number of approaches you can take that would solve this problem. These solutions could involve an initial mutual agreement which can force all intermediate nodes to act as intermediate nodes without refusing to forward any data packet which comes to them.
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