Janus: An Active Middleware for Accessing Sensor Networks

We present an indirection architecture for the Internet called SelNet. SelNet provides a uniform indirection mechanism for controlling the route that packets take through the network and which functions are invoked to process these packets. In the current Internet, at least for the majority of users, there is only one way that a packet can go and that is to the default route. Whilst this is sufficient for many applications, numerous applications have arisen which require alternative routes or processing to be present not only at the application-layer of the protocol stack, but at the network-layer itself. Solutions to such scenarios attempt to place an indirection point between the communicating end-systems either with a middlebox (such as a proxy) or by altering one or more of the Internet's naming systems. However these approaches lead to an application-specific network, which is against the Internet's design goals. We argue for a uniform approach to indirection instead of building multiple, partially overlapping structures as is the current trend. SelNet differs from existing indirection approaches in that it is function-orientated, rather than node-orientated and that it provides an explicit, controllable resolution mechanism for resolving host names and services. The motivation behind our approach is to create efficient indirection structures for supporting new applications which have indirection requirements. We present a detailed design and specification of SelNet. We then go on to describe implementation work with the LUNAR ad-hoc routing protocol and the Janus middleware for accessing sensor networks systems. The purpose of this implementation work is to demonstrate the feasibility of SelNet and its ability to reach its goals.