QsNet

QsNet is a high speed interconnect designed by Quadrics used in HPC clusters, particularly Linux Beowulf Clusters. Although it can be used with TCP/IP; like SCI, Myrinet and Infiniband it is usually used with a communication API such as MPI or SHMEM called from a parallel program.

The interconnect consists of a PCI card in each compute node and one or more dedicated switch chassis. These are connected with a copper cables. Within the switch chassis are a number of line cards that carry "Elite" switch ASICs. These are internally linked to form a fat tree topology. Like other interconnects such as Myrinet very large systems can be built by using multiple switch chassis arranged as spine (top-level) and leaf (node-level) switches. Such systems are usually called federated networks.

As of 2003, there are two generations of QsNet. The older QsNetI was launched in 1998 and used PCI 66-64 cards that had 'elan3' Custom ASIC on them. These gave an MPI bandwidth of around 350 Mbyte/s unidirectional with 5us latency. QsNet II was launched in 2003. It used PCI-X 133 MHz cards that carry 'elan4' ASICs. These give an MPI bandwidth of 912 Mbyte/s and MPI latency starting from 1.22us, performance depends on platform used.

In 2004 Quadrics started releasing small to medium switch stand-alone switch configurations called QsNetII E-Series, these configurations range from the 8 to the 128-way systems.

External links

* [http://www.quadrics.com Quadrics website]
* [http://doc.quadrics.com/Quadrics/QuadricsHome.nsf/DisplayPages/3A912204F260613680256DD9005122C7 Quadrics QsNet Page]
* [http://doc.quadrics.com/Quadrics/QuadricsHome.nsf/DisplayPages/476637E138359A1C80256E6A0059B85B Quadrics 8-way]