Large Hadron Collider: Worldwide LHC Computing Grid 2007

The Worldwide LHC Computing Grid (WLCG) is the world’s largest computing and data grid with 30,000 CPUs at 200 sites. It will process and deliver LHC data from the detectors to physicists at their home institutions. While LHC data will be transported from CERN over dedicated 10Gbps lightpaths to Tier1 sites across the globe, the traffic from the Tier1 centers to the data analysis facilities at the Tier2 centers flows over shared international Research & Education networks. The actual data analysis by physicists will take place at Tier2 sites.

Indiana University; Purdue University; University of California, San Diego: Tier2 Sites
The Large Hadron Collider (LHC) Compact Muon Solenoid (CMS) is an electronic detector that is searching for subatomic particles, especially a particle known as Higgs boson, which is a missing piece in the jigsaw puzzle of the theory of particle physics (boson is the name physicists give subatomic particles with particular properties). Dubbed “the God Particle” nearly a decade ago by Nobel prize-winning physicist Leon Lederman, the Higgs boson would explain why some particles have any mass at all, while others, such as photons, do not.

Internationally there are 11 Tier1 sites and more than 100 Tier2 sites. In the US, the 7 CMS Tier2 sites are Purdue University, University of California, San Diego, Caltech, University of Nebraska, University of Wisconsin, University of Florida and MIT. They will receive CMS data from Fermilab (a Tier1 site). Data will be processed and then analyzed by university physicists. (Brookhaven is a Tier1 for the CERN ATLAS project.) In tests so far, the CMS Tier2 sites have been able to support up to 50,000 jobs per day, and the goal is to be able to support 100,000 computing jobs per day by late spring.

Purdue and UCSD are the only two Tier2 sites connected to NSF’s TeraGrid research network, and Purdue also connects to Fermilab through StarLight and Indiana’s I-Light. Indiana University plays a key role in CERN’s ATLAS project, which, like the CMS project, aims to discover insights into subatomic physics and the nature of matter.

Brazilian Tier2 Sites
There are two Tier2 groups in Brazil – Universidade do Estado do Rio de Janeiro (UERJ) and Universidade Estadual Paulista (UNESP)/Universidade de São Paulo (USP) – who want to connect to Tier1 and CERN at 1Gbps rates. Efforts are underway for WHREN-LILA to connect via TransLight/StarLight.

Australian Tier2 Sites
Physicists at the Universities of Melbourne and Sydney work closely with AARNet and computing partners at APAC in Canberra, VPAC in Melbourne, AC3 in Sydney and SAPAC in Adelaide to prepare and build the Australian nodes of the WLCG for LHC ATLAS data. Data from the Asia-Pacific regional Tier1 center in Taipei to the Tier2 federation in Australia is expected to top 300Mbps at full data rates. Delivering high network throughput from Taipei to Tier2 centers is only possible with assistance from AARNet’s network engineers, in cooperation with local university networks and international network partners.

URL: (Tier1 and Tier2 sites)

Collaborating LHC Tier1 Centers:






Denmark, Finland, Norway, Sweden:
Nordic Data Grid Facility



Rutherford Appleton Laboratory

Brookhaven National Laboratory
Fermi National Accelerator Laboratory

Collaborating LHC Tier2 Centers (Participating countries):
Australia, Austria, Belgium, Brazil, China, Czech Republic, Finland, France, Germany, India, Israel, Italy, Japan, Norway, Pakistan, Poland, Portugal, Romania, Russia, Slovenia, Spain, Sweden, Switzerland, Taiwan, UK, Ukraine, USA