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Proceedings Paper

Bulk data transfer distributer: a high performance multicast model in ALMA ACS
Author(s): R. Cirami; P. Di Marcantonio; G. Chiozzi; B. Jeram
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Paper Abstract

A high performance multicast model for the bulk data transfer mechanism in the ALMA (Atacama Large Millimeter Array) Common Software (ACS) is presented. The ALMA astronomical interferometer will consist of at least 50 12-m antennas operating at millimeter wavelength. The whole software infrastructure for ALMA is based on ACS, which is a set of application frameworks built on top of CORBA. To cope with the very strong requirements for the amount of data that needs to be transported by the software communication channels of the ALMA subsystems (a typical output data rate expected from the Correlator is of the order of 64 MB per second) and with the potential CORBA bottleneck due to parameter marshalling/de-marshalling, usage of IIOP protocol, etc., a transfer mechanism based on the ACE/TAO CORBA Audio/Video (A/V) Streaming Service has been developed. The ACS Bulk Data Transfer architecture bypasses the CORBA protocol with an out-of-bound connection for the data streams (transmitting data directly in TCP or UDP format), using at the same time CORBA for handshaking and leveraging the benefits of ACS middleware. Such a mechanism has proven to be capable of high performances, of the order of 800 Mbits per second on a 1Gbit Ethernet network. Besides a point-to-point communication model, the ACS Bulk Data Transfer provides a multicast model. Since the TCP protocol does not support multicasting and all the data must be correctly delivered to all ALMA subsystems, a distributer mechanism has been developed. This paper focuses on the ACS Bulk Data Distributer, which mimics a multicast behaviour managing data dispatching to all receivers willing to get data from the same sender.

Paper Details

Date Published: 27 June 2006
PDF: 8 pages
Proc. SPIE 6274, Advanced Software and Control for Astronomy, 62741E (27 June 2006); doi: 10.1117/12.671159
Show Author Affiliations
R. Cirami, INAF-Osservatorio Astronomico di Trieste (Italy)
P. Di Marcantonio, INAF-Osservatorio Astronomico di Trieste (Italy)
G. Chiozzi, European Southern Observatory (Germany)
B. Jeram, European Southern Observatory (Germany)

Published in SPIE Proceedings Vol. 6274:
Advanced Software and Control for Astronomy
Hilton Lewis; Alan Bridger, Editor(s)

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