With wireless ad hoc sensor networks, there is simultaneously a need and an opportunity to optimize the protocol stack behavior to match the sensor-based applications. A general-purpose internet stack is neither appropriate nor sufficient to meet the needs of such applications. Motivated by this observation, we pose two related questions: (a) What is an appropriate layering of the protocol stack for future sensor networks? (b) How do we make the network stack tunable to a specific sensor application? We present the design of a new protocol stack, and we qualitatively argue that the new stack is more suitable to meet the demands of sensor network applications than traditional stacks.