The Square Kilometer Array – A next generation scientific instrument and its implications for networks

The Square Kilometer Array – SKA – is a radio telescope consisting of several thousand antennae spread over a million sq. km. that operate as a single instrument to provide an unprecedented astronomy capability, and in the process generates an unprecedented amount of data that have to be transported over networks. Commensurate with its scale, the collaboration associated with the SKA involves some 70 institutions in 20 countries. The data rates from the individual antenna results in a total data flow to a correlator / data processor of up to 9 Pb/s. This is reduced to the science data product which is a 100 Gb/s steady-state data flow that must be transported to the collaborators spread around the world. The sheer volume of data and the number of networking components needed to transport the raw and partially processed data are staggering. For example, assuming 10 Gb/s optical channels with Ethernet interfaces on the antennae and the correlator, the inner area, which has about 50% of the antennae, requires almost 200,000km of fiber and of order a million 10G Ethernet and optical channels must be provisioned. This represents an operational and maintenance scale that is completely unknown in the R&E community. Finally, the transport of the 100 Gb/s data product around the world presents some interesting higher level problems. In this paper we will discuss the networking issues in more detail and based on experience with the LHC at CERN, suggest some approaches to addressing the issues.



  • William E. Johnston
  • Senior Scientist, ESnet, Lawrence Berkeley National Laboratory
  • e-mail: wej@es.net
  • Roshene McCool
  • Domain Specialist in Signal Transport and Networks, SKA Program Development Office, Jodrell Bank Centre for Astrophysics
  • e-mail: mccool@skatelescope.org

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