Simulators for wireless sensor networks are a valuable tool for
system development. However, current simulators
can only simulate a single level of a system at once. This makes
system development and evolution difficult since developers
cannot use the same simulator for both high-level algorithm
development and low-level development such as device-driver implementations.
We propose cross-level simulation, a novel type of wireless
sensor network simulation that enables holistic simultaneous
simulation at different levels. We present an implementation of such a
simulator, COOJA, a simulator for the Contiki sensor node operating
system. COOJA allows for simultaneous simulation at the
network level, the operating system level, and the machine code
instruction set level. With COOJA, we show the feasibility of the
cross-level simulation approach