Wi-Fi Offload: Tragedy of the Commons or Land of Milk and Honey?

Fueled by its recent success in provisioning on-site wireless Internet access, Wi-Fi is currently perceived as the best positioned technology for pervasive mobile macro network offloading. However, the broad transitions of multiple collocated operators towards this new paradigm may result in fierce competition for the common unlicensed spectrum at hand. In this light, our paper game-theoretically dissects market convergence scenarios by assessing the competition between providers in terms of network performance, capacity constraints, cost reductions, and revenue prospects. We will closely compare the prospects and strategic positioning of fixed line operators offering Wi-Fi services with respect to competing mobile network operators utilizing unlicensed spectrum. Our results highlight important dependencies upon inter-operator collaboration models, and more importantly, upon the ratio between backhaul and Wi-Fi access bit-rates. Furthermore, our investigation of medium- to long-term convergence scenarios indicates that a rethinking of control measures targeting the large-scale monetization of unlicensed spectrum may be required, as otherwise the used free bands may become subject to tragedy-of-commons type of problems.Comment: Workshop on Spectrum Sharing Strategies for Wireless Broadband Services, IEEE PIMRC'13, to appear 201

Research as a Service: The Role of Competence Centers in Bridging Industry and Academia

Turning research results into commercial success has been one of the key economic challenges since the beginning of the industrial revolution. In this context, most recently an increasing impact of Public Private Partnership (PPP) approaches can be observed. In this chapter, we focus on a specific form of PPP which aims at establishing so-called “Competence Centers”, i.e. research institutions explicitly joining the forces of academic and industrial research. Based on two examples in the Austrian funding program COMET, we describe the basic setup of such centers, and discuss the specific roles and challenges for various types of research staff, including their roles and career paths. Finally, we sketch the most important lessons learned, before we conclude with a brief summary and outlook

Adaptive multi-path routing for internet traffic engineering

Zsfassung in dt. SpracheDie vorliegende Arbeit stellt das Adaptive Multi-Path Routing (AMP) als einen neuen Algorithmus für dynamisches Traffic Engineering im Internet vor. Das Hauptziel des AMP besteht darin, die Last innerhalb einer Netzdomäne dynamisch zu verteilen, um die überlasteten Verbindungen und Pfade in Realzeit, entsprechend der momentanen Verkehrssituation und den vorhandenen Ausweichmöglichkeiten, zu entlasten. Im Gegensatz zu verwandten Ansätzen, die den Verkehr auf mehrere Pfade aufteilen, führt AMP als seine wichtigste Innovation die Einschränkung der Lastsignalisierung auf den lokalen Umkreis einer Verbindung ein und ermöglicht somit sowohl eine Verringerung der Signalisierungslast, als auch des Speicherbedarfs in den Routern. Dabei ist hervorzuheben, dass AMP trotz seiner lokalen Signalisierungsarchitektur eine globale Ausbreitung der Lastinformation innerhalb der gesamten Netzdomäne ermöglicht und so zu einer effizienten Behandlung von Überlastsituationen im Netz führt. Darüber hinaus stellt diese Arbeit sowohl einen ausführlichen Überblick über die relevante Theorie und die daraus abgeleiteten Ansätze vor, als auch eine tiefgehende Leistungsbewertung des Algorithmus in zwei unterschiedlichen Simulationsumgebungen, die IP-Netze entweder auf Paket- oder auf Flussebene abbilden, und in denen jeweils die gesamte Funktionalität von AMP implementiert wurde. Die untersuchten Simulationsszenarien stellen dabei den letzten Stand der Technik dar, indem ausgeklügelte Topologie- und Verkehrsmodelle verwendet werden, um eine hohe Übertragbarkeit der Erkenntnisse in die Realität zu ermöglichen. Die Ergebnisse der durchgeführten Leistungsbewertung demonstrieren in konsistenter Weise die Effizienz der durch AMP erzielten Lastverteilung, und sie unterstreichen auch das stabile Verhalten des Algorithmus in allen untersuchten Szenarien. Anschließend wird in einer etwas allgemeineren Betrachtung die momentane Bedeutung von Traffic Engineering im aktuellen Kontext der IP-Netze diskutiert, wonach zum Schluss noch wichtige potentielle Anwendungsgebiete für AMP im Bereich von neuen Netzlösungen und -architekturen dargestellt werden.The present thesis proposes Adaptive Multi-Path routing (AMP) as a novel algorithm for dynamic traffic engineering in the Internet. The main objective of AMP is to distribute load within a network domain in a continuous manner, trying to offload congested links and paths by responding to the observed traffic conditions in real-time. In contrast to similar multi-path routing proposals, the central innovation of AMP lies in the restriction of the exchange of load information to a local scope, thus achieving a significant reduction of signaling overhead and memory consumption in the routers. Most importantly, in spite of its local nature, AMP's signaling mechanism nevertheless enables global propagation of congestion information, leading to an efficient handling of overload events in the network. Apart from providing an extensive overview of the related theory and approaches, this thesis introduces and discusses AMP in depth, after which an exhaustive performance evaluation of the algorithm is presented. This evaluation is carried out using two distinct simulation environments, which model IP networks either at the level of individual packets or individual flows, and for both of which the full functionality of AMP has been implemented in detail. Furthermore, the investigated simulation scenarios represent the state-of-the-art concerning the choice of topologies and traffic models, thus offering a comprehensive insight into the algorithm's behavior in real systems. The results of the performance evaluations consistently demonstrate AMP's efficiency in terms of load balancing performance, and they also underline the stable behavior of the algorithm throughout the investigated scenarios. Finally, the thesis discusses traffic engineering in the current context of IP networks on a more general level, before it presents important potential areas of application for AMP in novel and emerging networking solutions and architectures.10

Inter-Domain Route Diversity for the Internet

Part 2: Economics and Technologies for Inter-Carrier ServicesInternational audienceThe current inter-domain routing in the Internet, which is based on BGP-4, does not allow for the use of multiple paths, but rather restricts the routing to a single path for each destination prefix. This fact is especially unfortunate considering the vast route diversity which is inherently present in the global Internet graph. Therefore, we propose Inter-Domain Route Diversity (IDRD) as an overlay mechanism which enables efficient, backwards compatible and incrementally deployable introduction of route diversity in the Internet. Beyond presenting the architecture of IDRD, this paper also presents the conditions which ensure the stability of the proposed mechanism as a fundamental prerequisite for its deployment in real-world scenarios

Adaptive Multipath Routing Based on Local Distribution of Link Load Information

Adaptive Multi-Path routing (AMP) is a new simple algorithm for dynamic traffic engineering within autonomous systems. In this paper, we describe an AMP variant which is related to the well-known Optimized Multi-Path (OMP) routing protocol. Whereas OMP requires global knowledge about the whole network in each node, the AMP algorithm is based on a backpressure concept which restricts the distribution of load information to a local scope, thus simplifying both signaling and load balancing mechanisms. The proposed algorithm is investigated using ns-2 simulations for a real medium-size network topologyand load scenarios by performing comparisons to several standard routing strategies.

Adaptive multipath routing for dynamic traffic engineering

Abstract–This paper proposes Adaptive Multi-Path routing (AMP) as a simple algorithm for dynamic traffic engineering within autonomous systems. In contrast to related multipath routing proposals, AMP does not employ a global perspective of the network in each node. It restricts available information to a local scope, which opens the potential of reducing signaling overhead and memory consumption in routers. Having implemented AMP in ns-2, the algorithm is compared to standard routing strategies for a realistic simulation scenario. The results demonstrate the stability of AMP as well as the significant performance gains achieved. I. INTRODUCTION AND RELATED WORK Efficient routing algorithms have always been among the core building blocks of any packet switching network. Whereas existing routing protocols are usually designed fo

Feasibility Aspects of AMP Performance Evaluation in a Fluid Simulation Environment

In order to address the problem of intra-domain IP traffic engineering efficiently, we have recently proposed Adaptive Multi-Path routing (AMP) as a dynamic algorithmic solution based on a local view of the network. For two real ISP topologies we have demonstrated that our scheme significantly improves network performance while generating only minimal signaling overhead. However, our performance evaluations have been accomplished by packet-level simulation, which has turned out to be a rather slow method as soon as realistic network sizes and traffic scenarios are considered, and thus prevents a deeper analysis of the algorithm. Therefore, we are currently developing a simulation environment which is based on the fluid model, i.e., focusing on flow aggregates instead of single packet events and connections, which makes it much faster than packet-level simulation. In this paper we describe the basic concepts of fluid models and evaluate the feasibility of fluid-based simulation of AMP, particularly concentrating on computational efficiency.

A SIMULATION STUDY OF MICROSCOPIC AMP BEHAVIOR

We have recently proposed Adaptive Multi-Path (AMP) routing as a novel algorithm for dynamic traffic engineering which provides significant performance improvements over competing routing strategies. In this paper we present microscopic investigations of the algorithm’s stability. Using a novel dedicated fluid simulation framework, several experiments have been carried out using appropriate topologies and traffic patterns. Our results demonstrate the consistently stable behavior of AMP routing throughout a variety of simulation scenarios, and further underline its applicability to intra-domain traffic engineering.