  In this paper we study coordinated multipath routing at the flow-level in
networks with routes of length one. As a first step the static case is
considered, in which the number of flows is fixed. A clustering pattern in the
rate allocation is identified, and we describe a finite algorithm to find this
rate allocation and the clustering explicitly. Then we consider the dynamic
model, in which there are stochastic arrivals and departures; we do so for
models with both streaming and elastic traffic, and where a peak-rate is
imposed on the elastic flows (to be thought of as an access rate). Lacking
explicit expressions for the equilibrium distribution of the Markov process
under consideration, we study its fluid and diffusion limits; in particular, we
prove uniqueness of the equilibrium point. We demonstrate through a specific
example how the diffusion limit can be identified; it also reveals structural
results about the clustering pattern when the minimal rate is very small and
the network grows large.
