by Peter Wunderling and Lothar Klein
At the end of 1993 GMD started to establish ATM based networks at its locations in Schloß Birlinghoven, Darmstadt, and Berlin to provide a testbed for next-generation computer applications with need of high bandwidth and as a backbone for the existing LANs.
The driving force behind the ATM activities of GMD is the rapidly increasing need of high bandwidth for computer applications with voice and video and for visualisation in general. Increasingly the various R&D projects of GMD (e.g. MAT - Multimedia Applications in Telecooperation) require bandwidth which cannot be provided by the existing LANs (e.g. Ethernet). Therefore GMD decided to establish ATM-based networks at its locations in Schloß Birlinghoven/Sankt Augustin, Darmstadt, and Berlin to provide bandwidth today of up to 155 MBit/sec. The ATM networks are being used as a platform for testing new applications (especially multimedia) and as a backbone for the existing LANs.
In a first step (February 1994), two ATM switches (ASX-100, Fore Systems) were installed at Schloß Birlinghoven and in Sankt Augustin. Both systems are connected via a fiber link (140 MBit/sec) leased from DBP Telekom. Soon after this ATM pilot network became operational, the MAT project could successfully show the first video applications running on top of ATM. In the GMD Laboratory for Parallel Computing, the first throughput measurements with a Sun cluster show a much better performance for the four Suns connected via ATM than via FDDI. The existing Ethernet infrastructure at both locations now has a backup solution in the 140 MBit/sec ATM link.
At GMD in Darmstadt a similar ATM network with two ASX-100 switches is in use. In Berlin at GMD FOKUS, an additional ASX-100 system has been integrated into ATM networks which already were operational within projects such as BERKOM and BALI.
In the next step (September 1994), two Hicom ATM-P switches (Siemens AG) will connect the ATM networks at GMD in Birlinghoven and Berlin with the "B-ISDN Pilot Network" of DBP Telekom. This broadband pilot network which has access points in Cologne/Bonn, Hamburg, and Berlin, offers ATM links with speeds of 2, 34.5, and 155 MBit/sec. The B-ISDN Pilot also allows GMD to participate in European ATM activities.
The ATM network in Darmstadt will be connected with the networks in Sankt Augustin and Berlin when the DFN association (German Research Network) offers its 34.5 MBit/sec academic network WiN (based on ATM technology and planned for 1995).
Furthermore it is planned to expand the ATM networks at all GMD locations and to make services available such as video on demand and video conferencing.
see figure: The ATM Pilot Network