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Abstract:Research backbone networks like GÉANT2 and the National Research and Education Networks are used by a variety of scientists and research projects. These users and the network engineers operating the networks would like to get access to network performance metrics to optimise their use of the network and to troubleshoot performance degradations, when they happen. A variety of tools for performing network measurements already exist, and the perfSONAR architecture developed within the Joint Research Activity 1 (JRA1) of GÉANT2 aims at integrating them in a coherent framework. However, a harmonised definition of which metrics are mostly interesting and how measurements must be carried out is still lacking. In this paper we suggest the set of elementary metrics which are more relevant, along with indication about how to post process (or "transform", or "compose") them in order to obtain derived summary values that can quickly and intuitively give an indication of network performance. Methods to perform the composition are presented, together with constraints which have to be taken into account to get accurate results. In particular, delay measurements are the most delicate ones to compose. We carried out a series of experiments for proofing the validity of composition of delay metrics, and we briefly present some preliminary results.

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Although network security is a crucial aspect for network operators, there are still very few works that have examined the anomalies present in large backbone networks and evaluated the performance of existing anomaly detection solutions in operational environments. The objective of this work is to fill this gap by reporting hands-on experience in the evaluation and deployment of an anomaly detection solution for the GÉANT backbone network. During this process, we analyzed three different commercial tools for anomaly detection and then deployed one of them for several months in the 18 points-of-presence of GÉANT. We first explain the general requirements that an anomaly detection system should satisfy from the point of view of a network operator. Afterwards, we describe the evaluation of the tools and present a study of the anomalies found in a continental backbone network after operationally using the finally deployed tool for half a year. We think that this first hand information can be of great interest to both professionals and researchers working on network security and can also guide future research towards more practical problems faced by network operators.