RFC 1306 (rfc1306) - Page 2 of 10
Experiences Supporting By-Request Circuit-Switched T3 Networks
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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
