Thierry Rakotoarivelo

OMF: a control and management framework for networking testbeds

Networking testbeds are playing an increasingly important role in the development of new communication technologies. Testbeds are traditionally built for a particular project or to study a specific technology. An alternative approach is to federate existing testbeds to a) cater for experimenter needs which cannot be fullled by a single testbed, and b) provide a wider variety of environmental settings at different scales. These heterogenous settings allow the study of new approaches in environments similar to what one finds in the real world. This paper presents OMF, a control, measurement, and management framework for testbeds. It describes through some examples the versatility of OMFs current architecture and gives directions for federation of testbeds through OMF. In addition, this paper introduces a comprehensive experiment description language that allows an experimenter to describe resource requirements and their configurations, as well as experiment orchestration. Researchers would thus be able to reproduce their experiment on the same testbed or in a different environment with little changes. Along with the efficient support for large scale experiments, the use of testbeds and support for repeatable experiments will allow the networking field to build a culture of cross verification and therefore strengthen its scientific approach.

Integrated personal mobility architecture: a complete personal mobility solution

The high expectations and demand for users to access the Internet from anywhere at anytime has made user mobility an important part of the design and development of the next generation mobile communications and computing. Traditionally user mobility has been divided into two areas: Terminal Mobility and Personal Mobility. In recent years terminal mobility has focused on the movement of the terminal and developed extensions to IP protocols such as Mobile IP. In contrast, personal mobility has only received limited attention, and is somewhat lagging behind. This research has either focussed on personal mobility in communications or personalisation of operating environments. As a result, to date no framework for providing true personal mobility has emerged. In this paper, we introduce a new personal mobility framework called IPMoA (Integrated Personal Mobility Architecture), which integrates both aspects of personal mobility to provide a complete personal mobility solution, and illustrate the viability of this approach through a proof-of-concept implementation.

Measurement Architectures for Network Experiments with Disconnected Mobile Nodes

Networking researchers using testbeds containing mobile nodes face the problem of measurement collection from partially disconnected nodes. We solve this problem efficiently by adding a proxy server to the Orbit Measurement Library (OML) to transparently buffer measurements on disconnected nodes, and we give results showing our solution in action. We then add a flexible filtering and feedback mechanism on the server that enables a tailored hierarchy of measurement collection servers throughout the network, live context-based steering of experiment behaviour, and live context-based control of the measurement collection process itself.

An instrumentation framework for the critical task of measurement collection in the future Internet

Abstract Experimental research on future Internet technologies involves observing multiple metrics at various distributed points of the networks under study. Collecting these measurements is often a tedious, repetitive and error prone task, be it in a testbed or in an uncontrolled field experiment. The relevant experimental data is usually scattered across multiple hosts in potentially different formats, and sometimes buried amongst a trove of other measurements, irrelevant to the current study. Collecting, selecting and formatting the useful measurements is a time-consuming and error-prone manual operation. In this paper, we present a conceptual Software-Defined Measurement (SDM) framework to facilitate this task. It includes a common representation for any type of experimental data, as well as the elements to process and collect the measurement samples and their associated metadata. We then present an implementation of this concept, which we built as a major extension and refactoring of the existing Orbit Measurement Library (OML). We outline its API, and how it can be used to instrument an experiment in only a few lines of code. We also evaluate the current implementation, and demonstrate that it efficiently allows measurement collection without interfering with the systems under observation.

Designing and orchestrating reproducible experiments on federated networking testbeds

Abstract In addition to theoretical analysis and simulations, the evaluation of new networking technologies in a real-life context and scale is critical to their global adoption and deployment. Federations of experimental platforms (aka testbeds) offer a controlled and cost-effective solution to perform such an evaluation. Most recent efforts in that area focused on building those facilities and providing experimenters with tools to allow the discovery and provisioning of their shared resources. Many challenges remain in order to support the complete experiment life cycle in a federated environment. We propose OMF-F, a framework which allows the definition of networking experiments and their execution over shared resources provided by different federated administrative domains. OMF-F provides a domain-specific language enabling rich event-based experiment descriptions. It defines a specific resource model and protocol, which together with its publish-subscribe messaging system allows automatic experiment orchestrations at a large scale. OMF-F further provides interfaces to operate with existing resource discovery and provisioning tools for federated testbeds. Our contributions in this paper are threefold. First we provide detailed descriptions of OMF-F’s design, its architecture, and its involved entities. Then, we present a quantitative evaluation of its underlying messaging and event-handling systems. Finally, we discuss two real examples of OMF-F deployed and used on federated domains to define and execute experiments.

A Portal to Support Rigorous Experimental Methodology in Networking Research

Whilst dealing with topics that are more and more influenced by physical properties of the underlying media, the networking community still lacks a culture of rigorous result verification. Indeed, as opposed to most of the science and engineering fields there are very few benchmarks to test protocols against. Furthermore, in most publications the authors do not give the community access to the raw results or details of the performed experimental procedures. Therefore it is impossible to accurately reproduce their experiments. We propose to solve this problem by extending the state of the art experiment tool OMF with a public portal. This portal, while providing the experimenter with access to experimental resources, also provides the community with a system for comprehensive experiment description and result verification. The collection of both the measurement set and the experiment’s description is done in a transparent manner for the experimenter, who can decide to publish them via the portal once the research is mature enough.

Enhancing qos through alternate path: an end-to-end framework

In the next generation Internet, the network should not only be considered as a communication medium, but also as an endless source of services available to the end-systems. These services (i.e. Overlay Applications) would be composed of multiple cooperative distributed software elements that dynamically build an ad hoc communication mesh (i.e. an Overlay Association). In this paper we propose and evaluate a collaborative distributed method to provide enhanced QoS between end-points within an overlay association.

Mobility emulator for DTN and MANET applications

Repeatable experiments to study the performance or behavior of wireless mobile adhoc network (MANET) systems such as a delay (or disruption) tolerant network (DTN) are challenging tasks. One approach to do this is to build a realistic mobile testbed, on which the mobile devices and test applications or network protocols can be deployed. This testbed approach, however, often results in expensive management and setup costs. Therefore, most of algorithms and applications considering device mobility as a critical parameter have been tested using trace-based analysis and computer simulations. However, these evaluation methods are not sufficient to reflect various natures of mobile wireless networks. This paper presents the design and implementation of an On/Off-based mobility emulation method, which virtually migrates applications over a static-grid testbed to mimic the device mobility. This emulation method assists DTN and MANET developers to evaluate their work in repeatable ways on the lab-scale static-grid testbed. Through extensive experimental analysis and a case study using two different testbeds, we show that the proposed emulation method can successfully recreate important characteristics of mobility trace data, such as contact and inter-contact time distributions.

A structured peer-to-peer method to discover QoS enhanced alternate paths

In the next generation Internet, the network should not only be considered as a communication medium, but also as an endless source of services available to the end-systems. These services (i.e. overlay applications) would be composed of multiple cooperative distributed software elements that dynamically build an ad hoc communication mesh (i.e. an overlay association). In a previous contribution, we proposed a collaborative distributed method to provide enhanced QoS between end-points within an overlay association. This method aims at discovering and utilizing composite alternate end-to-end paths that experience better QoS than the default path given by the IP routing mechanisms. In this paper we present our investigations on a modification to this method. This modification aims at improving its scalability by structuring participating nodes into a coordinate space and by using an alternative scheme to construct the lists of candidate relay nodes for the alternate path discovery method.

Experimentation in Heterogeneous European Testbeds through the Onelab Facility: The Case of PlanetLab Federation with the Wireless NITOS Testbed

The constantly increasing diversity of the infrastructure that is used to deliver Internet services to the end user, has created a demand for experimental network facilities featuring heterogeneous resources. Therefore, federation of existing network testbeds has been identified as a key goal in the experimental testbeds community, leading to a recent activity burst in this research field. In this paper, we present a federation scheme that was built during the Onelab 2 EU project. This scheme federates the NITOS wireless testbed with the wired PlanetLab Europe testbed, allowing researchers to access and use heterogeneous experimental facilities under an integrated environment. The usefulness of the resulting federated facility is demonstrated through the testing of an implemented end-to-end delay aware association scheme proposed for Wireless Mesh Networks. We present extensive experiments under both wired congestion and wireless channel contention conditions that demonstrate the effectiveness of the proposed approach in a realistic environment. Both the architectural building blocks that enable the federation of the testbeds and the execution of the experiment on combined resources, as well as the important insights obtained from the experimental results are described and analyzed, pointing out the importance of integrated experimental facilities for the design and development of the Future Internet.