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.
