RFC 1306 (rfc1306) - Page 2 of 10
Experiences Supporting By-Request Circuit-Switched T3 Networks
Alternative Format: Original Text Document
RFC 1306 Experiences with Circuit-Switched T3 March 1992
Overview
Users of wide-area networks often must make a compromise between low
cost and high speed when accessing long haul connections. The high
money cost of dedicated high speed connections makes them
uneconomical for scientists and engineers with limited budgets. For
many traditional applications this has not been a problem. Datasets
can be maintained on the remote computer and results were presented
in a text-only form where a low-speed connection would suffice.
However, for visualization and other data transfer intensive
applications, this limitation can severely impact the usability of
high performance computing tools which are available only through
long-haul network connections.
Supercomputers are one such high performance tool. Many users who
can benefit from access to supercomputers are limited by slow network
connections to a centrally located supercomputer. A solution to this
problem is to use a circuit-switched network to provide high speed
network connectivity at a reduced cost by allocating the network only
when it is needed.
Consider how a researcher using a visualization application might
efficiently use a dedicated low speed link and a circuit switched
high speed link. The researcher logs in to the remote supercomputer
over the low speed link. After running whatever programs are
necessary to prepare the visualization, the high speed connection is
activated and used to transfer the graphics data to the researcher's
workstation.
We built and demonstrated this capability in September, 1990, at the
Telecommunications Association show in San Diego, using this type of
visualization application. Further, it will be available in a
forthcoming release of our system software.
Architectural Model
We developed our support for circuit switched services around a
simple model of a switched network. At some point in the path
between two hosts, there is a switched network connection. This
connection is likely to connect two enterprise networks operated by
the same organization. Administrative overlap between the two
networks is useful for accounting and configuration purposes. We
believe that with further investigation circuit switched network
support could be extended to multiple switched links in an internet
environment.
The switch which makes the network connection operates on a "by-
request" basis (also called "on-demand"). When it receives a request
Nicholson & Young