Embedded Computing Design - OpenSystems Media

Because Infiniband can incorporate other fabrics, it can efficiently connect storage and
communications networks and server clusters together, while delivering an I/O infrastructure
that will produce the efficiency, reliability, and scalability that data centers demand.
Unlike Ethernet, Infiniband requires little to no processor load, making it better suited
for data-intensive applications. Also, it enables the processor to share memory, although
systems incorporating this fabric still suffer from slower processing speeds.
The PCI Express approach
PCI Express, originally introduced by Intel in 2001 as 3GIO (3rd Generation I/O), was
designed to provide higher bandwidth and faster speed as well as to address chip-to-chip
connections, out-of-the box connections, and add-on-card connections. It consists of
multiple, point-to-point serial connections called lanes that can be used to create an I/O
interconnect with a linearly-scalable bandwidth.
PCI Express also enables processors to
share some system resources, such as
memory, increasing the functionality of
the overall system.
The StarFabric standard
Also an extremely popular switch fabric,
StarFabric was originally developed by
StarGen. The organization now tasked
with the development and promotion
of this standard is the StarFabric Trade
Association (www.starfabric.org), also
a nonprofit, open membership industry
group.
StarFabric is an open interconnect standard
that provides high levels of scalability,
performance, and availability in a wide
range of systems. It supports multiple
classes of traffic for added flexibility and
enhancements to systems while leveraging
existing standards-based software and
hardware investments.
As with Infiniband and PCI Express,
StarFabric enables the resources of a
system to be shared, including memory,
which enables the load on the processor
to be greatly reduced.
RapidIO…the future fabric
of choice
RapidIO, the last of the open interconnect
standards that we’ll discuss, was designed
to be compatible with the most popular
integrated communications processors,
host processors, and networking digital
signal processors.
According to the RapidIO Trade
Association (www.rapidio.org), it is a
high-performance, packet-switched,
interconnect technology that addresses the
embedded industry’s need for reliability,
increased bandwidth, and faster bus
speeds in an intrasystem interconnect. The
RapidIO interconnect allows chip-to-chip
and board-to-board communications at
performance levels scaling to ten gigabits
per second and beyond.
RapidIO has had some significant advancements
take place over the past few
months. In December 2003, the International
Standards Organization (ISO)
and the International Electrotechnical
Committee (IEC) ratified the RapidIO 1.2
interconnect specification as ISO/IEC DIS
18372. To date, RapidIO is the only one
of the over 60 switch fabrics currently
available to receive this designation.
RSC #26 @ www.embedded-computing.com/rsc
The ratification of a standard by ISO
(www.iso.ch) requires that both vendors
and end users of the technology develop
the standard in an open forum that fosters
26 / Summer 2004 Embedded Computing Design