The tight limitations in energy, processing power and memory, which call
for highly optimized and lightweight protocols; and,
4. The collaborative objective for which all the sensor nodes cooperate with
one another.
In order to account for all of the above factors, it is necessary to optimize
the communication protocols, to best satisfy the application level objectives.
Any other design considerations, such as protocol layering, are secondary.
Non-traditional design principles like cross-layer integration and applicationspecific
design, are recommended and even necessary, to make the protocols
lightweight and energy-e?±cient. In fact, it is neither easy nor cost-e?®ective,
to devise a generic framework to design communication protocols for WSNs.
This is because each WSN application imposes a unique set of goals and
requirements, and also produces a di?®erent type of data tra?±c.
Consider the following two scenarios. First consider an application to monitor
the environmental conditions a?®ecting crops and livestock. Now this is a
???data gathering??? application. The data tra?±c it generates is expected to be
more or less uniform, and the latency requirements on its data are expected
to be loose. It is important in this case, to find and maintain energy-e?±cient
routes to convey all the sensed information to the sink node(s). On the other
hand, a sensor network deployed to detect forest fires is likely to produce data
in rare bursts with severe latency constraints.
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