Johan Bergs

A novel network architecture for train-to-wayside communication with quality of service over heterogeneous wireless networks

In the railway industry, there are nowadays different actors who would like to send or receive data from the wayside to an onboard device or vice versa. These actors are e.g., the Train Operation Company, the Train Constructing Company, a Content Provider, etc. This requires a communication module on each train and at the wayside. These modules interact with each other over heterogeneous wireless links. This system is referred to as the Train-to-Wayside Communication System (TWCS). While there are already a lot of deployments using a TWCS, the implementation of quality of service, performance enhancing proxies (PEP) and the network mobility functions have not yet been fully integrated in TWCS systems. Therefore, we propose a novel and modular IPv6-enabled TWCS architecture in this article. It jointly tackles these functions and considers their mutual dependencies and relationships. DiffServ is used to differentiate between service classes and priorities. Virtual local area networks are used to differentiate between different service level agreements. In the PEP, we propose to use a distributed TCP accelerator to optimize bandwidth usage. Concerning network mobility, we propose to use the SCTP protocol (with Dynamic Address Reconfiguration and PR-SCTP extensions) to create a tunnel per wireless link, in order to support the reliable transmission of data between the accelerators. We have analyzed different design choices, pinpointed the main implementation challenges and identified candidate solutions for the different modules in the TWCS system. As such, we present an elaborated framework that can be used for prototyping a fully featured TWCS.

Analysis of End-User QoE in Community Networks

Community networks are a potential model for the Future Internet, where the users form and operate the network instead of a central, commercial entity. The performance of parts of community networks has been studied extensively, often focusing on routing protocols or applications on top of community networks. This work focuses on the end-to-end quality of experience in community networks, as a validation of the technical applicability of this concept in under-served regions. A comparative analysis with other ISPs per country shows the effectiveness of these community networks in providing satisfactory networking services to end-users, particularly effective for underserved areas or people. Socio-economic studies show that community networks are an excellent model to develop networking infrastructure commons (as common-pool resources or public goods) that promote sustainable development, with greater effects in less developed areas.

Data traffic differentiation and QoS on the train, in fast parameter varying, heterogeneous wireless networks

Although Internet on the train and train to wayside communication in general becomes more and more available for train operators, there are still a lot of challenges for future research. We previously developed a network platform that is responsible for an uninterrupted and seamless connectivity from the train to the wayside through heterogeneous wireless access technologies. This paper mainly focuses on the concept for providing sufficient Quality of Service (QoS) guarantees in a dynamic train environment. Within this network platform, IPv6 strategies are adopted for QoS, exploiting multi-homing and intelligent aggregation techniques. The implementation that has been done in the Click Modular Router programming environment will also be presented in details.

The ADAMO project: Architecture to support communication for emergency services

When emergency services are in a crisis situation, one of their major needs is to have efficient communication. Every person involved needs to have the most up-to-date and relevant information at all times and needs to be able to communicate with his colleagues effectively. In order to support this, it is important that the network used by the emergency services supports all necessary communication flows to make this communication as smooth as possible. In this paper, we will describe the end-to-end system architecture we developed and implemented in the IBBT1 project ADAMO - Advanced Disaster Architecture with Mobility Optimizations.

Impact of introducing road charging on supporting mobile data networks

This paper presents a model for assessing the impact of introducing nationwide road charging systems on supporting mobile data networks. It defines a model based on real traffic measurements, and establishes appropriate parameter values for capturing specific application characteristics such as the importance of data compression, truck-only versus all traffic charging, and dimensioning margins for handling peak days. Finally, this paper applies the developed model and defined parameter values to a Belgian case study.

Design and prototype of a train-to-wayside communication architecture

Telecommunication has become very important in modern society and seems to be almost omnipresent, making daily life easier, more pleasant and connecting people everywhere. It does not only connect people, but also machines, enhancing the efficiency of automated tasks and monitoring automated processes. In this context the IBBT (Interdisciplinary Institute for BroadBand Technology) project TRACK (TRain Applications over an advanced Communication networK), sets the definition and prototyping of an end-to-end train-to-wayside communication architecture as one of the main research goals. The architecture provides networking capabilities for train monitoring, personnel applications and passenger Internet services. In the context of the project a prototype framework was developed to give a complete functioning demonstrator. Every aspect: tunneling and mobility, performance enhancements, and priority and quality of service were taken into consideration. In contrast to other research in this area, which has given mostly high-level overviews, TRACK resulted in a detailed architecture with all different elements present.

Mapping a community network

Community networks are self-organized networks which exist all around the world. For a large number of users, they are the only form of communication in the community itself and with the Internet. All community networks maintain some database where all information about the nodes in the community network is stored. The database information is manually inserted in the database, which commonly leads to a mismatch between the documentation and reality. In this paper we present a dynamic community network mapper, complementary to the node database. We explain the goals of this approach, show the challenges and steps we took to realize such a mapper, and give initial results.

Comparing Community Networks to the Internet: An Empirical Study of BGP Behaviour

Community networks are a new, emerging form of organising local network access and access to the public Internet where people themselves operate and build their networks. However, little research has been performed on the stability of the resulting bottom-up infrastructure. In this work, the BGP behaviour of community networks is empirically studied by evaluating dumps of BGP messages from the AWMN and Guifi community networks and comparing the results to data from the public Internet. The preliminary results show that community networks are significantly less stable, although the public Internet shows a significantly higher ratio of update messages over withdrawal messages.

Traffic Differentiation - A Basic Step Towards Providing End-to-End QoS on the Train-to-Wayside Wireless Communication System

We developed a network platform that is responsible for an uninterrupted and seamless connectivity from the train to the wayside through heterogeneous wireless access technologies. However, limiting the offered services to only an onboard Internet is not a feasible business case. A viable one should extend to a broad spectrum of railway communication services like: train control, diagnostics, real time passenger information, entertainment, security CCTV surveillance etc. In a highly dynamic environment (from the communication link point of view) such a fast moving train, it is necessary to introduce prioritization among different traffic classes. This will implicitly determine under what conditions a certain flow should get suspended or dropped in order to preserve the flows of a higher priority as long as possible and to ensure that they meet their QoS demands. The first step towards this goal is data traffic differentiation.