CERN1 has made another important step forward in high-speed computing and state of the art networking. On 15 September a Gigabyte System Network (GSN) network with a capacity of 10 Gbit per second ramped up successfully at CERN, connecting together computers from different computer companies (Compaq, IBM, SGI and Sun).
It is the first time worldwide that GSN-PCI interfaces are demonstrated in a real network with computers from so many different manufacturers. This technological breakthrough was possible as newly developed interfaces for the universally used PCI/PCI-X bus have become available.
CERN will develop these new networking technologies further in collaboration with industrial partners. CERN needs them to handle the gigantic quantities of data that new experiments in High Energy Physics will produce in the future. At the same time, fast long distance connections will be needed to distribute this data to collaborating High Energy Physics Institutes where it will be analysed.
This project helps to raise computing and networking performance to new highs that will support many new applications in the next decade. The rapidly growing Internet will profit from faster response times from service providers. Video on demand that makes intensive use of fast networked storage will become widespread. Health care will benefit from better remote diagnoses made possible by the transfer of very high resolution medical images.
CERN also demonstrated the new Scheduled Transfer (ST) technology, a faster and more direct protocol than today's Internet Protocol for direct data transfer and storage. This protocol can be used with all standard network technologies such as Gigabit Ethernet. The demonstration at CERN was made up of two Storage Area Networks (SAN), one coupled to the GSN network and one coupled to Gigabit Ethernet. The latter used the new ST protocols and a cluster file system (SANergy) for the first time ever.
There is a tendency in today's networking to merge Local Area Network and Wide Area Network technologies by using Ethernet protocol directly over fibre optic wavelengths as a cheaper alternative to the conventional synchronous digital hierarchy (SDH). CERN demonstrated for the first time that GSN and Gigabit Ethernet networks can be bridged directly to SDH technology with a speed of 2.5 Gbit/s over an OC48c/SDH16 fibre optic connection. This latter bridge interface was recently developed at CERN together with the US company Genroco Inc.
Some Technical Definitions
Using the Peripheral Computer Interface is how most computers communicate with the outside world. It comes in three different speeds of which PCI-X is the fastest.
Gigabyte System Network is an ANSI and ISO standard for a 10 Gbit/s network running over parallel copper links (since 1998) and fibre optics connections (just developed at CERN in 2000). For comparison: GSN is around 1000 times faster than standard Ethernet, and 10 times faster than Gigabit Ethernet.
GSN bridges allow connection of various types of networks without appreciable delay for protocol conversion. For the moment, connections to a GSN bridge are possible for HIPPI, Fibre Channel, SONET OC48c/SDH16 and Gigabit Ethernet. The last two are CERN/Genroco developments.
Scheduled Transfer is a protocol that permits both high bandwidth and low delay data transport with less computing load than older protocols. An extension to ST is "SST" or SCSI over ST, which allows storage commands to be sent directly over standard network hardware links.
A Storage Area Network is a facility for storage that is coupled directly to a network and not to a particular host computer. It normally consists of groups or "arrays" of hard disks which can be connected via switches to various hosts.
OC48c is a substandard for data transmission over SONET, the Serial Optical NETwork standard. OC stands for Optical Connection and 48 indicates the speed of 2.5 Gbit/s. SDH16 is the European equivalent of this Synchronous Digital Hierarchy. Compared to a V90 modem, OC48c/SDH16 is around 50 000 times faster.
10 Gigabit Ethernet
10 GigE is a development that is now under way to extend the Ethernet hierarchy (10, 100 and 1000 Mbit/s today) to a speed of 10 Gbit/s.
iSCSI is a development project to move storage commands over the Internet Protocol. It does not have the advantages of SST in a limited distance network, but may have some advantages in storage access over long distances. For more information: Arie Van Praag +41 22 767 5034.