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

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.