الفهرس 
Overview
TCP/IP network OverlayOnly 14 pages are availabe for public view
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Abstract
Wireless sensor networks (WSN) envision a ubiquitous computing future in many fields, like environmental monitoring, military surveillance, and inventory tracking. Wireless sensor networks are composed of large numbers (up to thousands) of tiny radio-equipped sensors. Every sensor node has a small microprocessor with enough power to allow the sensors to autonomously form networks through which sensor information is gathered. Sensor nodes in such networks are ad hoc deployed, self-configurable and battery powered. A set of special protocols are developed for such networks to fit their specific characteristics.
Many wireless sensor network applications cannot run in complete isolation; the sensor network must be connected to monitoring and controlling entities through known wireless/wired networks like IP-based networks. Such interconnection achieves many advantages and increases sensor networks benefits such as:
• Controlling and monitoring sensor networks remotely.
• Integrating data collected from sensor networks into data repositories.
• Ability to collapse multiple remote sensor networks into one virtual sensor network.
A few approaches recently manipulate this issue and they are categorized into two main approaches: gateway-based and network overlay. The first approach uses a gateway node to interconnect both networks and bring data from WSN to the IP network. It so allows choosing WSN communication protocols freely. The second approach overlays the protocol stack of one network by the protocol stack of the other network. Overlaid nodes become an intersection area among both networks through which they are integrated.
In this thesis, an integration technique is proposed. This technique supports both address-centric and data-centric WSNs. It uses a low-level gateway node to translate packets from one network to the other. Thus, it allows choosing WSN communication protocols that are most suitable for the sensor network application. Furthermore, it depends on a simple translation operation and does not require modification to be made in protocols running in either network. Therefore, it can be used in different applications with no need to modify the gateway logic. Moreover, this technique provides transparent communication between both networks which allows interconnection with no need to know details about the protocols of the other side.
The proposed technique is implemented on the OMNeT++ simulator for both address-centric and data-centric paradigms. Experimental results show that it supports accessing individual sensor nodes from IP hosts with high request rates without significantly influencing the network performance. For example, when an IP host sends requests to sensor nodes up to 150 requests per second, the average of overhead delay is about 0.25 milliseconds with 0.5% average increase in the packet loss. On the other hand, it also supports accessing data-centric WSN with different sizes and through simultaneous queries (interests). For example, when an IP host propagates up to 20 simultaneous interests, the median overhead delay is about 4.3 milliseconds with 6.5% decrease in the delivery ratio at maximum. The proposed integration technique, however, suffers from bottleneck and single point of failure problems which should be investigated in future work.