Setup

The DAS cluster⁴ is a super computer formed by a large number of Intel processors running Free BSD or Linux and locally connected by Myrinet, a popular Gigabit LAN. There are DAS Clusters operational at the Dutch universities which are specified in table 3.

 

Table: Dutch universities where the DAS clusters are located. Please note that the Title columns refer to the titles used in the net performance Web pages and the Full Name columns refer to the university names used in the English home pages.

The DAS clusters are inter-connected by an ATM network. Often there also exists a route via the ``usual'' Internet. The connection to the network is served by gateway hosts which are running Free BSD or RedHat Linux. There was a need in the DAS community to monitor the network performance a.o. to compare the ATM connection to the ``usual'' Internet route.

This is realized by installing the test host scripts of the RTPL package at the gateways of the DAS clusters at each of the four universities. A Digital Unix host from the ``Department of Computational Physics'' at the ``Faculty of Physics & Astronomy'', Utrecht University, is used as the control host. The HTTPD server of the faculty is used for the Web⁵ presentation. This could be done without extra actions, because the directory with results is also accessible from the host where the HTTPD server resides.

The performance measurements were executed via the ATM network and also via the ``usual'' Internet route. However, not all gateways did have an Ethernet interface which was accessible from the WAN. Therefore, some tests across the regular Internet had to be skipped. Skipped tests are marked in the result tables with ``--''. The tests were performed only in one direction. The reason is that the network performance in the ATM network is expected to be rather symmetric.