Abstract-In this paper we consider the problem of constructing a coordinate system in a sensor network where location information is not available. To this purpose we introduce the Virtual Coordinate assignment protocol (VCap) which defines a virtual coordinate system based on hop distances. As compared to other approaches, VCap is simple and have very little requirements in terms of communication and memory overheads. We compare by simulations the performances of greedy routing using our virtual coordinate system with the one using the physical coordinates. Results show that the virtual coordinate system can be used to efficently support geographic routing.

In this paper we propose an output queued switch architecture based on the mesh of trees topology. We establish the equivalence of our proposal with the output queued model, with respect to a large variety of queuing techniques, and we analyze its features, showing that in principle it could be a practical solution to guarantee quality of service. Moreover, such an architecture is able to easily and efficiently manage multicast traffic, which is becoming extremely important in order to offer multimedia (specially voice and video) services over the network.

Abstract. In this paper we propose an architecture for an output queued switch based on the mesh of trees topology. After establishing the equivalence of our proposal with the output queued model, we analyze its features, showing that it merges positive features of the input queued switches (specially their implementability) with all the characteristics typical of output queued ones. Moreover, such an architecture is able to easily and efficiently manage multicast traffic, which is becoming extremely important in networks with traditional communication services integrated in.