PPE-level protocols for carpet clusters

We describe the lowest level of a suite of protocols for workstation cluster multicomputers: the parts implemented in hardware by a Protocol Processing Engine (PPE) and the software level immediately above the PPE. The stated goal of this work is extremely low end-to-end latency communications on independent workstations connected by a packet switching communication fabric. The workstations are expected to run a commercial operating system and must present the same security characteristics as traditional protocols. We begin with a realization of sender-based protocols. Such protocols can avoid much of the copying that slows down traditional approaches and can also reduce the overhead involved in demultiplexing packet streams and notification of recipients. Finally, we present some measurements of an early prototype.