Metrology techniques and tools for the Internet and its traffic

The Internet is undergoing a transformation in terms of its uses. Twenty years ago, the Internet was a single-service network for transporting binary or text files. Today, it must be a multi-service network for transporting a wide variety of data, such as audio and video (films, video-on-demand, telephony, etc.).

In fact, the network needs to undergo a technological transformation to make it capable of transporting, with adequate and multiple QoS (Quality of Service), the different types of information offered by all the applications using the Internet.

However, attempts to guarantee this quality of service have failed, not least because of a complete lack of understanding of its traffic and the reasons for its complexity. In the end, as it exists today, no one has control or even complete knowledge of the network, which works against the implementation of multiple quality-assured communication services.

Internet network metrology – literally "the science of measurement" applied to the Internet and its traffic – should provide an answer to these problems.

First of all, if we are to provide services with predefined qualities, we need to be able to measure them.

On the other hand, metrology must provide answers to questions concerning the Internet traffic model(s) that are currently lacking. Today, network metrology, a recent science if ever there was one – it emerged in the early 2000s – is changing the whole process of Internet network research and engineering, and becoming its cornerstone.

Internet metrology breaks down into two distinct tasks, the first of which involves measuring the physical parameters of the quality of service offered by the network, or traffic.

In a network the size and complexity of the Internet, this is already – as we shall see – a complex task. However, this measurement and observation activity only highlights visible phenomena. However, in a network, what is certainly even more important is to deduce the causes, i.e. to determine the components and/or protocol mechanisms that generate them. We find ourselves faced with the same problem as Plato in his allegory of the cave. In his cave, where a wood fire was crackling, Plato could only see the shadows of the men prowling the cave. The shadows cast on the walls of the cave were immense, suggesting that they were those of giants. Network metrology – QoS measurement or simple traffic analysis – confronts us with this "Platonic" problem: it only shows...