Bypassing the traffic jams on the information superhighway

A taxi without a driver, controlled from the other end of the world? Quite conce
A taxi without a driver, controlled from the other end of the world? Quite conceivable in the age of the internet. © Damian Gorczany
In order to travel from A to B in Berlin, you don’t need a local taxi driver. Your cab could just as well be driven from Brazil - provided that the data packets are delivered reliably and, above all, quickly.

A taxi driver navigating his cab through the city. A surgeon performing a procedure at the operating table. "These close spatial relationships are in the process of dissolving," points out Professor Steffen Bondorf. The computer scientist heads the Chair of Distributed and Networked Systems in the Faculty of Computer Science at Ruhr University Bochum, Germany. The doctor could control her surgical instruments from anywhere, saving patients a stressful and time-consuming trip to a specialist clinic. For safety to be maintained, signals must reliably get from one place to another quickly. Steffen Bondorf calculates whether they do. Rubin, the science magazine of the Ruhr-Universität Bochum, reports on this.

The more traffic, the longer the queue

Steffen Bondorf is pursuing is trying to provide a mathematical proof of the speed and reliability of data transmission. It is a rather complex matter: "The internet is a huge system with countless components," points out the researcher. "We simply can’t tackle it as a whole, but have to study its individual elements."

Each section of the route and each node at which they are relayed affects the speed at which they progress. Here, the same rules apply as on the highway: the more traffic there is, the longer you have to wait and the slower your progress will be.

Technical conditions, standards and priority levels determine how long it takes in each case. Bondorf uses what is known as the network calculus to model the path of data travelling from A to B. All stations and interfaces that the data passes through are incorporated into the model, including abstractions of their technical specifications. "One reason this works is because the organisation of the internet is strictly hierarchical," explains the researcher. "Data traversing this hierarchical structure tends to take the shortest route to the next higher node and back again."

Tool is available

For the modelled case, a transmission time from A to B is set and must not be exceeded. To perform the calculation, the researcher assumes error-free conditions. The analysis then produces a single value: an upper bound on the maximum delay of data packet transport.

Steffen Bondorf makes his analysis tool available under a permissible open-source license. "I do assume that enterprises that operate networks or develop components will utilise the results of my research," he says. However, it is usually difficult to obtain information from the industry as they protect their intellectual property by secrecy. Even when it comes to implementing standards, we have to trust that the companies follow the specification in its very detail, because they don’t disclose their source code. "As far as I’m concerned, the question of what’s theoretically possible is the core motivation behind my research efforts," he concludes, reflecting on his academic interest. "I want to understand the systems."