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Communication nodes are typically composed of multiple
subsystems,each performing designated functions such as LAN
interface, routing,format conversion, and high-level
applications , etc.. Multiple subsystems are tightly coupled
together to achieve the aggregated system functions and
objectives by exchanging data and controls. Conventional
backplane buses are uneffective means for the interconnection
of multiple subsystems in broadband communication nodes,such as
local ATM switches and super-hubs in Local Area Networks(LANs),
because of the bandwidth inadequacy and physical distance
constraint. The Multi-subsystem Interconnect(MSI)is intended as
a scalable platform to facilitate the physical coupling and
information exchange among multiple subsystems. The MSI is
based on the fast-packet switching. Implemented on backplanes,
it provides virtual channels for switching of level-2
information in sybsystems' memories , which are sent in 53
bytes packets by the MSI in hardware. The core of the MSI
consists of a switching fabric and its control. The structure
of the switching fabric provides multiple paths into each
destination. Multi-cast is the inherent property of the fabric.
Routing controls of packets are skewed to the switching fabric
control one packet-time ahead. This pipe-line approach time
constraint in performing any conflict resolutions,resulting
simple logic design of the switching fabric control. The MSI
subsystems will be highly reusable, in addition to having
overhead-free communication and flexible physical
interconnection capabilities. The MSI applications include
local ATM switches, LAN superhubs, high performance bridges/
routers, and broadband bandwidth managers.
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