ABSTRACT
To understand anomaly detection in networks, we must have a good understanding of basic network concepts. We also must understand how anomalies may arise in networks. This chapter provides the necessary background to both of these topics. The first part of the chapter discusses networking basics, components of networks, types of networks, scales of networks, topologies of networks and performance constraints. The second part introduces the concept of network anomalies, causes of anomalies, sources of anomalies and their precursors. It also presents a classification of network intrusions or attacks.
