We have developed a scalable sensor network simulation framework called sQualnet [1]. sQualnet is based on the well-known Qualnet simulator; it benefits from Qualnet’s greater scalability, realistic and detailed propagation models, and support for easing model development. sQualnet features a rich suite of detailed and accurate sensor network specific models, including: sensing and radio channels, sensor protocols (MAC, routing), battery and power consumption models, support for multi-tiered sensor network evaluations. The observed network performance is highly dependent on the model accuracy, as shown in [2]. Besides, sQualnet provides real code simulation capability for motes [3]. Specifically, it allows the use of unmodified TinyOS applications (written in NesC) and SOS applications (written in C), thereby enabling easy transition between simulation and real experimentation on a deployed sensor network. Through the aforementioned features, sQualnet overcomes limitations of existing sensor network evaluation tools. Compared to common wireless network simulators (e.g., ns-2, OPNET, Qualnet) and other sensor-specific simulators (e.g., SensorSim), sQualnet has the additional capability for real-code simulation. With its support for accurate radio propagation models, it also addresses a key limitation of existing real-code simulators (e.g., TOSSIM) and hardware emulators (e.g., ATEMU). In addition, sQualnet offers hybrid simulation capability to support varying degrees of integration of real and simulated network components, which can aid in system development and enable large-scale evaluations in a cost-effective manner. Using this capability, one can model a network where some nodes are simulated while the rest are real physical nodes, or where some layers of the network