Towards Distributed Protocol Stacks for Wireless Sensor Networks

In this paper, we propose a model that uses remote procedure call (RPC) techniques to overcome the code size constraints of existing protocol stacks for wireless sensor networks (WSNs). In this model, neighboring nodes share one or more layers of their communications stack with each other in a cooperative fashion. In this way, the use of the protocol stack on each node without the need to include the stack's full programming logic on every node is enabled. At the same time, transparent interconnectivity is preserved by forming a Distributed Protocol Stack (DPS). This allows the use of an existing stack on more resource-constrained nodes or the integration of additional layers from different hard- or software platforms. We give an overview on the concept behind DPS and on the preliminary protocol specification. Furthermore, we describe our prototypical implementation on the iSense WSN platform. This implementation lets nodes with more memory share their IPv6 layer with more resource constrained neighboring nodes, allowing the seamless exchange of IP packets between all nodes in the network. We evaluate our implementation against a native IPv6 implementation with respect to code size, memory usage, round-trip time and UDP goodput.