We present a new model for the distributed implementation of pi-like calculi. This model is a close match to a variety of calculi, and so permits strong correctness results that are easy to prove. In particular, we describe a distributed abstract machine called the fusion machine. In it, only channels exist at runtime. It uses a form of concurrent constraints called fusions - equations on channel names - which it stores as trees of forwarders between channels. We implement in the fusion machine a solos calculus with explicit fusions. There are encodings into this calculus from the pi calculus and the explicit fusion calculus. We quantify the efficiency of the latter by means of (co-)locations.