636
M. Delfino
Fig. 14.2 Schematic view of the original ATLAS computing model
Fig. 14.3 Schematic view of the original CMS computing model
As mentioned earlier, the detailed breakdown of tasks performed at each Tier
depends on the computing model of each experiment. On the other hand, the
Tier-0 and most Tier-1 sites serve multiple experiments, whereas most Tier-2 sites
only serve a single experiment. This leads to quite complex optimization issues,
especially in regards to data transmission, which depending on the experiment
may involve few or many site pairings. For example, Figs. 14.2 and 14.3 show
schematically the original computing models for the ATLAS and CMS experiments,
and the different connectivity patterns between Tiers can clearly be seen. Originally,
ATLAS closely linked a given Tier-1 to a group of Tier-2 sites, and hence the data
flows in a more “hierarchical” fashion. The original CMS model had a focus on
M. Delfino
Fig. 14.2 Schematic view of the original ATLAS computing model
Fig. 14.3 Schematic view of the original CMS computing model
As mentioned earlier, the detailed breakdown of tasks performed at each Tier
depends on the computing model of each experiment. On the other hand, the
Tier-0 and most Tier-1 sites serve multiple experiments, whereas most Tier-2 sites
only serve a single experiment. This leads to quite complex optimization issues,
especially in regards to data transmission, which depending on the experiment
may involve few or many site pairings. For example, Figs. 14.2 and 14.3 show
schematically the original computing models for the ATLAS and CMS experiments,
and the different connectivity patterns between Tiers can clearly be seen. Originally,
ATLAS closely linked a given Tier-1 to a group of Tier-2 sites, and hence the data
flows in a more “hierarchical” fashion. The original CMS model had a focus on