No. 51 (00163)

Family name : Kozlovszky
Given name : Miklos
Affiliation : CERN (Switzerland) 
Abbreviation : 
E-mail address : miklos.kozlovszky@cern.ch
Title : Developing a transport layer component for the DAQ framework of
        the CMS Experiment
Authors : M. Kozlovszky on behalf of CMS collaboration
Abstract : 
The CMS collaboration is currently investigating various different
networking technologies that may meet the requirements of the CMS Data
Acquisition System.  During this study a peer transport component based
on TCP/IP has been developed using object-oriented techniques for the
distributed DAQ framework named XDAQ.  This framework was designed to
facilitate the development of distributed data acquisition systems
within the CMS Experiment.  The peer transport component was designed to
meet 3 main requirements.  Firstly, it had to provide fair access to the
communication medium  for competing applications. Secondly, it had to
provide as much of the available bandwidth to the application layer as
possible. Finally it had to hide from the application layer, the
complexities of using non-blocking TCP/IP connections.

This paper describes the development of the peer transport component and
then presents and draws conclusions on the measurements made during
tests.  The major topics investigated include: blocking versus
non-blocking communication, TCP/IP configuration options, multi-rail
connections and the use of hyper-threading.