Is cross-platform protocol stack suitable for sensor networks? Empirical evaluation

Software for sensor networks is usually coupled with the operating system (OS) and suffers from numerous limitations. For example, developers cannot examine their programs with their favorite simulators or debugging tools, and they must focus on low-level system issues. Although some research efforts introduced middleware abstractions to support software portability, communication protocols are still tightly coupled with the OS. We argue that the complete protocol stack, starting at the MAC layer, does not have to be coupled to an OS and can be implemented as Cross-Platform software. It allows porting across many OSs and network simulators. As a proof-of-concept, we developed Medium Access Control (MAC) and routing protocols, and integrated them with three OS: TinyOS, Reflex, and BanOS. Although portable protocols require extra adaptation layers (AL), the memory and delay penalty are within reasonable limits. For example, the AL needs from 1.1 kB to 5.8 kB extra memory, depending on the OS. Furthermore, the delay caused by AL spans from dozens to hundreds of microseconds for various operations. In typical scenarios these delays have almost no impact on energy consumption. That is, if nodes with native applications running atop TinyOS work 2.5 years, the AL shortens the lifetime by 2 hours only.