Publikationen 2011

The future wireless telecommunication environment is characterized by the co-existence of a multitude of wireless networks such as LTE, LTE-Advanced, UMTS, WiMAX, WiFi etc. In order to be able to offer the best connectivity, according to the requirements of the users and to the preferences of the operator, a novel functionality was introduced in the core network and in the mobile devices for access network discovery and selection. This paper introduces this functionality as standardized in the 3GPP Evolved Packet Core (EPC), highlighting its main concepts and technical scenarios. Further, a set of novel optimizations are presented and evaluated, followed by the description of their implementation as part of the Fraunhofer FOKUS OpenEPC toolkit.

Telecommunication and Internet services are constantly subject to changes, seeking the customer's full satisfaction. Enriching these services with innovative approaches such as context-aware, social, mobile, adaptable and interactive mechanisms enable users to experience a variety of personalized services seamlessly across different platforms and technologies. In this sense, Service Oriented Architectures play a central role in allowing component reuse and low cost service creation. Together with IP Multimedia Subsystem enable the convergence of telecommunications and web services, allowing the network transport technologies to be abstracted from the services above. By integrating these technologies, a number of synergies can be explored. Existing services can be easily enriched with context information, made available on a variety of networks and new services can be composed using previously existing building blocks. This paper explains how this integration can be achieved, and demonstrates the potentialities of this architectural paradigm with a prototype service.

Networks, services, and business models need to be piloted in a large-scale environment that mimics as far as possible the Internet and its future version, although we certainly do not know what this will look like. In this highly demanding and dynamic context, new frameworks and (meta-) architectures for supporting experimentation are proposed, aiming at discovering how existing and emerging testbeds and experimental resources can be put together in such a way that testing and experimentation may be carried out according to specific requirements (industry, academia, etc.). The work presented in this article addresses a number of the fundamental principles and their corresponding technology implementations that enable the provisioning of large-scale testbeds for testing and experimentation as well as deploying future Internet platforms for piloting novel applications. The proposed concepts and architecture of Panlab, a pan-European testbed federation, aspires to facilitate and support user needs in these new areas.

This doctorate thesis introduces a framework for information and communication technology resource federation. Resource federation in the context of this work is a concept for sharing and allowing access to heterogeneous resources across multiple administrative domains. Three design artifacts are delivered as the main research result: a federation model, a federation methodology, and a system instantiation. The artifacts abstract from the types of resources to be federated. Examples of resources include general-purpose physical and virtual machines, software packages and systems, as well as specialized proprietary devices. Resource capabilities are exposed in a service oriented manner and can be assembled in meaningful combinations and configurations to satisfy the service consumer's requirements. One of the potential user segments is the scientific community where resources are requested for running large scale research experiments that require a certain setup of heterogeneous resources. The benefit provided to users of the federation is the seamless access to a large collection of resources via unified interfaces. Resource providers benefit from an additional sales channel, increasing their average resource utilization, some sort of compensation for the provided services, and the access to additional user groups. A federation organization maintains relationships with all stakeholders and offers central services to ensure the overall operation.

A framework for lowering the borders of service delivery and service composition in telecommunication networks is proposed in this work. In our opinion such an agile framework is needed for two main reasons. At first the cycle of introducing new services in the telecommunication industry usually takes several months, while the general cycles in the Web domain are much faster. Besides, customers want to use a flexible amount of services from different kinds of sources (e.g. Google, Facebook). The proposed agile service environment is intended to interact with services of the traditional telecommunication industry and is enabling the third party development process to support services coming from all kind of domains. Service platforms for Next Generation Networks adapting the principles of Service Oriented Architectures and the initial steps in the standardization towards service delivery frameworks are done. Special requirements that have to be considered are aspects of servicelife-cycle management and service composition that are critical regarding high performing real-time communication processes as needed in a telecommunications environment. Beyond the requirements of dynamic service deployment, management, evolution and service termination there is the intention of a well performing agile service composition mechanism. In order to fulfill the discussed requirements some related work in this area is presented and the promising IT / Network standards are enlightened. Furthermore, the architectural design of the developed framework is presented. Finally the paper demonstrates a practical use case scenario that shows the dynamic integration and combination of telecommunication services with services of the Web domain.

Resource federation is a concept for sharing information and communication technology (ICT) resources beyond administrative domains. The aim is to implement some common service drawing upon the resources committed by participating organizations. This concept is currently applied in a number of projects to provide large scale experimental facilities serving Future Internet research and development. In this paper we show how federated distributed resources can be described in terms of a common information model to support distributed resource management and Future Internet experimentation.

Currently, a number of research activities worldwide focus on resource federations to enable remote resource access and the setup of large scale experiments. With the global efforts in sharing experimental facility resources across organizational boundaries, interoperability issues are becoming increasingly important. To this end, this paper describes a model that defines the necessary entities for inter resource federation scenarios. The model is then discussed by means of a concrete use case federating Panlab and PlanetLab resources. In this respect Panlab and PlanetLab are considered to be federations themselves. Our findings show that the two approaches can be matched following the general model. This allows for federating resources not only across the boundaries of administrative (organizational) domains but even across the boundaries of federations. Those federations in themselves provide collections of resources offered by several administrative domains and use different control frameworks to enable resource access and management.

The challenging and ever increasing requirements of future applications demand new concepts for better control and management of network resources. The Third Generation Partnership Project (3GPP) introduced in their latest specifications the Evolved Packet Core (EPC) architecture for transparently unifying the parameters of different technologies, like the UMTS, WLAN, non-3GPP access technologies and a future Evolved Radio Access Network, called Long Term Evolution (LTE), with the use of multiple application platforms such as IP Multimedia Subsystem (IMS) and the Internet. This paper describes a testbed implementation of the Evolved Packet Core named OpenEPC which provides a reference implementation of 3GPPs EPC developed by the Fraunhofer Institute FOKUS. OpenEPC is a set of software com ponents offering advanced IP mobility schemes, policy-based QoS control, and integration with different application platforms in converging network environments. This initiative, in addition to fostering research and development, enables academic and industry researchers to rapidly realize state-of-the-art NGMN infrastructures and application testbeds.

Mobility in a wireless heterogeneous scenario in which the mobile devices are able to connect to more than one access technology available in their vicinity requires a re-consideration of the access network reselection mechanisms as to ensure seamless handovers for real deployments. This paper describes and evaluates a new proactive vertical handover optimization which enables a fast reselection, independent and in addition to the classic proactive procedures, using as a central concept that in specific conditions, the access network selection functionality located in the network should trigger a network internal proactive procedure which does not imply a high usage of the target access network resources according to the probability that a handover will be necessary in the near future as t o reduce the actual handover delay. This concept is exemplified on the 3GPP Evolved Packet Core and evaluated on a minimal prototype implementation.

Service-Oriented Network Architecture, Multimedia, Quality of Service, Internet housekeeping

In diesem Projekt werden die in den AV Vorlesungen NGN und FIT erworbenen Kenntnisse durch praktische Programmieraufgaben vertieft. Dabei werden mit Blick auf Exzellenz und Nachhaltigkeit in kleinen Gruppen neue Komponenten, Schnittstellen, Anwendungen und Werkzeuge fuer die AV/FOKUS OSTP, Next Generation Mobile Networks und FI Testbeds entwickelt. Die genauen Themen sind der AV Homepage zu entnehmen unter www.av.tu-berlin.de.

In diesem Projekt werden die in den AV Vorlesungen NGN und FIT erworbenen Kenntnisse durch praktische Programmieraufgaben vertieft. Dabei werden mit Blick auf Exzellenz und Nachhaltigkeit in kleinen Gruppen neue Komponenten, Schnittstellen, Anwendungen und Werkzeuge für NGN und FI Testbeds entwickelt die bei AV/Fraunhofer FOKUS zum Einsatz kommen. Die Technologien kommen aus den Bereichen Service Composition und Web Mash Ups, Identity and Policy Management, Converged Instant Messaging, IP-TV, Videostreaming, Infrastructure as a Service, Virtualisation.

In diesem Projekt werden die in den AV Vorlesungen NGN und FIT erworbenen Kenntnisse durch praktische Programmieraufgaben vertieft. Dabei werden mit Blick auf Exzellenz und Nachhaltigkeit in kleinen Gruppen neue Komponenten, Schnittstellen, Anwendungen und Werkzeuge fuer die AV/FOKUS OSTP, Next Generation Mobile Networks und FI Testbeds entwickelt. Die genauen Themen sind der AV Homepage zu entnehmen unter www.av.tu-berlin.de.

In diesem Projekt werden die in den AV Vorlesungen NGN und FIT erworbenen Kenntnisse durch praktische Programmieraufgaben vertieft. Dabei werden mit Blick auf Exzellenz und Nachhaltigkeit in kleinen Gruppen neue Komponenten, Schnittstellen, Anwendungen und Werkzeuge fuer die AV/FOKUS OSTP, Next Generation Mobile Networks und FI Testbeds entwickelt. Die genauen Themen sind der AV Homepage zu entnehmen unter www.av.tu-berlin.de.

In dieser VL werden grundlegende Konzepte, Architekturen, Protokolle, und Schnittstellen von aktuellen und zukünftigen Offenen Dienstplattformen auf der Basis konvergierender Netzwerktechnologien wie drahtlose und drahtgebundene Telekommunikationsnetzwerke, Next Generation Networks (NGNs) und Next Generation Mobile Networks vorgestellt. Insbesondere werden vorgestellt: VoIP, das IP Multimedia Subsystem (IMS) , aktuelle Entwicklungen des Evolved Packet Core und das Zusammenspiel der grundlegenden Technologien: SIP, Diameter, SIP Server, Media Server, Application Server, Service Delivery Platforms wie Telco JSON APIs, Telco JSON APIs, IN/CAMEL, OSA/Parlay, JAIN Web2.0 Mash ups, etc.