Title: Characterisation of router and link failure processes in UNINETT's IP backbone network

Authors: Andres J. Gonzalez; Bjarne E. Helvik

Addresses: Centre for Quantifiable Quality of Service in Communication Systems, Norwegian University of Science and Technology, O.S. Bragstads Plass 2E, N-7491, Trondheim, Norway. ' Centre for Quantifiable Quality of Service in Communication Systems, Norwegian University of Science and Technology, O.S. Bragstads Plass 2E, N-7491, Trondheim, Norway

Abstract: Backbone networks must be highly reliable. The offered availability can be predicted prior to operation if the stochastic behaviour of network components is known. The aim of this paper is provide information about failures and repairs processes in an operational network. Operational logs from UNINETT's core network were analysed to obtain distributions of the time between failures and downtimes of routers and links. The network components were classified according to their role in the network. The measured processes were fit with well-known distributions. The inter-failure times of routers and short distance links may be characterised by a Weibull distribution, but for the long distance links the gamma distribution yielded a better characterisation. The difference is discussed based on the hazard function. The parameters of each network component are made available and provide a detailed insight that may be used for dependability predictions and research.

Keywords: network dependability; failure characterisation; Weibull distribution; gamma distribution; failure rate; hazard function; link failure; router failure; backbone networks; network reliability; downtime.

DOI: 10.1504/IJSSC.2012.045564

International Journal of Space-Based and Situated Computing, 2012 Vol.2 No.1, pp.3 - 11

Received: 04 Jul 2011
Accepted: 21 Nov 2011
Published online: 20 Sep 2014 *

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