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Revista Facultad de Ingeniería - Universidad de Tarapacá

versión On-line ISSN 0718-1337

Rev. Fac. Ing. - Univ. Tarapacá v.11 n.1 Arica jun. 2003

http://dx.doi.org/10.4067/S0718-13372003000100004 

  REVISTA FACULTAD DE INGENIERÍA, U.T.A. (CHILE), VOL. 11 Nº1, 2003, pp. 25-32

AVAILABILITY EVALUATION OF NETWORKS: AN APPROACH FOR N-TIER CLIENT SERVER ARCHITECTURE

Flávia S. Coelho1     Jacques P. Sauvé2     Cláudia B. Abbas3

[1] U. Católica de Brasília, Brasil, Phone: +55-610-356-9314 Fax: +55-83-356-3010, fcoelho@uch.br

[2] U. Federal de Campina Grande, Dept. de Sistemas e Computação, Brasil, Phone: +55-83-310-1120, Fax: +55-83-310-1124, jacques@dsc.ufcg.edu.br

[3] U. de Brasília , Dept. Engenharia Elétrica, Lab. Redes, Faculdade de Tecnologia, Brasil, Phone: +55-61-3072308 Fax: +55-61-274-6651, barenco@redes.unb.br


ABSTRACT

Published work on computer network reliability frequently uses availability as a performance measure. However, although several ways of defining availability have been proposed, none capture the overall level of service obtained by client hosts in a modern n-tier client/server architecture. We propose such a measure by calculating the fraction of client hosts receiving complete services from the network. We also extend a published, efficient heuristic method for calculating availability to take into account our new proposed measure. The end result is a procedure of polynomial complexity O(nt4), where nt is the total number of components (hosts, links and interconnection equipment) in the network. Numerical results of applying the method to several networks are given.

Keywords: Evaluation of availability, network availability, dependability, n-tier client/server architecture


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Recibido el 19 de noviembre de 2002, aceptada el 02 de septiembre de 2003.