ATM TECHNOLOGY IMPLEMENTED BY PRAGUE ACADEMIC NETWORK

ATM - Asynchronous Transfer Mode - is for sure one of the most frequent terms used today when speaking about the future of telecommunications, of Internet. Some of the readers may know that ATM technology has already reached Prague as well and know what PASNet (Prague Academic Network) means. For the others we provide this article as means of information.

(http://www.cuni.cz/pasnet/pasnet.html)

PASNet - being developed since 1992, is a computer network servicing primarily academic institutions within Prague such as universities - Charles University, Czech Technical University, University of Economy, some high schools and institutions related to education. It is basically the academic Internet in Prague.

PASNet as a matropolitan area network is connected to the CESNet (Czech Education and Scientific Network) backbone. Charles University Computer Science Centre team is responsible for development and operation of this net and is heading all the related activities. Of course, it is a joint effort of all the participating institutions.

First, let us recall the historic development of PASNet. The respective locations were equipped with Cisco router (ranging from IGS to AGS+) since 1992, leased line with speed 64kbps were used to interconnect them. Since the 1993 it became obvious that we cannot stay with the leased lines for the future development of the network (because of low speed and limited reliability). After some discussion, the choice was to use the optical fibers of the Metronet network (optical fibers in the subway tunnels, operated by Dattel company). The year 1994 was thereof the year of building the optical connections from the first six most loaded locations (these were some of the locations of Charles University, Czech Tech University and University of Economics) to the nearest subway stations.

The tender for equipment took about 5 months to resolve, as we received quite some good proposals and we were discussing heavely the pros and cons of each solution (as ATM was really premature in the summer 1994). Finally, we decided for Cisco Systems equipment - ATM switch Cisco A100 and Cisco 7000/7010 series routers with ATM interface cards. The topology of the cabling is star with the center at the Charles University historical building Karolinum. We use STM-1 over single-mode fibers. The technology itself was delivered and after smooth instalation and configuration went to service on the very end of 1994.

Since then we connected some other locations with optical fibers (ATM and Ethernet, respectively). Having implemented ATM for the PASNet, this network became one of the first metropolitan ATM networks in service. Together with the new supercomputer facilities installed also at the Karolinum building, this combined technology equipment allows to use the PASNet in a qualitatively new way - new demanding applications are used (molecular modelling with remote X access, distributed computing clusters, Mbone, ...), some are being prepared (medical imaging). Looking back at this project now, after about half a year of operation, it turns out to be major achievement.

Zbynek Linhart