Network measurement is a field in its own right, which seeks to meet the needs of operators and users (human or application) by characterizing network operation and the service provided. As a result, the term "network measurement", or "metrology", refers to a range of methodologies, applications, metrics to be monitored, and so on. What's more, depending on the technology implemented in the network to be characterized, the methods employed can be very different. We are interested in measurement in IP networks, and in particular in estimating the network service delivered to applications or users.
This article describes the fields of application of metrology, and the methods that can be used to carry out measurements.
Section One shows how measurements can be used to understand network operation and characterize user traffic. This information is essential for implementing security mechanisms, planning network dimensioning and assessing network quality of service.
Section two presents standardized metrics, and details three metrics for evaluating the quality of service offered by the network.
Section three is dedicated to architectures implementing measurement in networks. The choice of architecture depends on the measurement objectives. In order to meet scaling and accuracy issues, measurement may require compromises.