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Scheduled Transfer

The Scheduled Transfer (ST) protocol is an ANSI-standard protocol that "bypasses" the operating system (OS) in order to deliver low latency and high bandwidth between communicating applications. This protocol, developed in tandem with HiPPI-6400/Gigabyte System Network, reduces inter-application latency times across a system-area network (SAN) by an order of magnitude when compared with a heavily-optimized TCP stack. OS-bypass protocols can achieve this low latency by having communicating hosts "pin" memory resources during a "scheduling phase" before the actual transfer. With the resources now scheduled for use, data is transmitted directly from application to application without OS intervention, thus eliminating OS system-call overhead such as buffering and processing delays.

Because ST has neither congestion control nor dynamic routing capabilities, ST is meant to support applications that require low latency and high bandwidth communication in a SAN, e.g., PC cluster. An example of an application that might require such performance (performance not currently possible with TCP) is real-time, interactive, computational steering in an immersive environment. This immersive environment may be used to support such Grand Challenge applications such as global climate modeling, genome sequencing, and large-scale hydrodynamics.

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