A linear forwarder is a process which receives one message on a channel and sends it on a different channel. Such a process allows for a simple implementation of the asynchronous pi calculus, by means of a direct encoding of the pi calculus’ input capability (that is, where a received name is used as the subject of subsequent input). This encoding is fully with respect to barbed congruence. Linear forwarders are actually the basic mechanism of an earlier implementation of the pi calculus called the fusion machine. We modify the fusion machine, replacing fusions by forwarders. The result is more robust in the presence of failures, and more fundamental.