SINK SINK SOURCE SINK SINK Channel Process C Process

The Internet and the Grid are changing the face of high performance computing. Rather than tightly-coupled SPMD-style components running in a single cluster, on a parallel machine, or even on the Internet programmed in MPI, applications are evolving into sets of cooperating components scattered across diverse computational elements. These components may run on diierent operating systems and hardware platforms and may be written by diierent organizations in diierent languages. Complete \applications" are constructed by assembling these components in a plug-and-play fashion. This new vision for high performance computing demands features and characteristics not easily provided by traditional high-performance communications middleware. In response to these needs, we have developed ECho, a high-performance event-delivery middleware that meets the new demands of the Grid environment. ECho provides eecient binary transmission of event data with unique features that support data-type discovery and enterprise-scale application evolution. We present measurements detailing ECho's performance to show that ECho signiicantly outperforms other systems intended to provide this functionality and provides throughput and latency comparable to the most eecient middleware infrastructures available.