Showing papers by "Thomas Magedanz published in 2007"

Evolution of SOA Concepts in Telecommunications

Abstract: The telecommunications industry has always been service-oriented. However, the convergence-driven need to deliver seamless services across different access networks has forced operators to embrace new approaches, including the intelligent network, Web-services-based APIs, and, most recently, the IP multimedia subsystem. Today, SOA is considered state of the art for service-delivery platforms. Such platforms for value-added services have evolved from the intelligent network (IN) and object-oriented programming interfaces to recent Web-services-based platforms. They've exploited the most recent information technologies to implement an open set of service components. Web 2.0's recent emergence, meanwhile, has further pressured telecom companies to implement an open service market based on an open set of enabling services and service components.

Denial of service attack and prevention on SIP VoIP infrastructures using DNS flooding

Abstract: A simple yet effective Denial of Service (DoS) attack on SIP servers is to flood the server with requests addressed at irresolvable domain names. In this paper we evaluate different possibilities to mitigate these effects and show that over-provisioning is not sufficient to handle such attacks. As a more effective approach we present a solution called the DNS Attack Detection and Prevention (DADP) scheme based on the usage of a non-blocking DNS cache. Based on various measurement conducted over the Internet we investigate the efficiency of the DADP scheme and compare its performance with different caching strategies applied.

VoIP defender: highly scalable SIP-based security architecture

Abstract: VoIP services are becoming increasingly a big competition to existing telephony services (POTS / ISDN). The increasing number of customers using VoIP makes VoIP services a valuable target for attackers that want to bring down the service, take it over or simply abuse it to distribute their own content, like SPAM. Hence, the need arises to protect VoIP services from all kinds of attacks that target network bandwidth, server capacity or server architectural constrains. In this article we present VoIP Defender, a generic security architecture, called VoIP-Defender, to monitor, detect, analyze and counter attacks relevant for a SIP-based VoIP infrastructure. The VoIP-Defender is highly scalable and can be easily extended with new detection algorithms. Analysis and traffic control can be performed from the SIP layer down to the transport-, network- and MAC layer. VoIP Defender is designed to work fully transparent to clients and SIP servers, and can analyze and filter traffic in real time, which we demonstrate with measurements with our implementation.

Development of an open source IMS core for emerging IMS testbeds, the academia and beyond

Abstract: The IP Multimedia Subsystem (IMS) as defined by the 3GPP emerges as blueprint for a central architecture to provide Next Generation Network (NGN) services. As an overlay architecture for IP based access networks, it provides standardized interfaces to services which will merge the advantages of traditional telephony networks with the benefits of Internet services. The Open IMS Core[1] project of the Fraunhofer Institute FOKUS which is described in this article started in 2006 as an Open Source initiative targeted at all parties interested in the research development of NGN services and IMS testbeds. The Open IMS Core consists of Call Session Control Functions and a Home Subscriber Server and aims to fill the void in the Open Source software landscape with flexible solutions that have proved their conformance and performance in several national and international R&D projects. This article highlights the challenges in the development of the components and provides insights on major implementation details as well as for their performance. Examples of the usage of the Open IMS Core will illustrate how IMS Open Source software helps not only rapid, but also efficient, flexible and powerful design, development and testing of NGN components and services.

Requirements for an IMS-based Quadruple Play Service Architecture

Abstract: Quadruple play can be understood as the provisioning of high-speed voice, video (live broadcast or on demand services, such as video on demand), and data services over broadband connections with mobility support. Currently, there are several trials of the IP multimedia subsystem deployed worldwide that promise to provide telecommunication and advanced multimedia services. This article focuses mainly on the basic requirements of a cooperative service delivery platform for provisioning quadruple play services. As a result of this research, an IMS-based cooperative service delivery platform is presented. This supports various access technologies to acquire the streaming services. To validate our quadruple play architecture, we implemented a prototype based on DVB-H and UMTS as the access technologies. This prototype is part of the ongoing development of the proposed architecture

Next Generation IPTV services for an extended IMS architecture

Abstract: Currently there is a strong discussion throughout the industry and all relevant standard development organizations (SDO) like the ITU-T and ETSI TISPAN how next generation IPTV services could incorporate with the developments from the TISPAN NGN Release 2 architecture. Several approaches have already been introduced struggling with the need for an integrated solution with the core IMS network or the development of a separated subsystem for next generation IPTV services. The main focus for the integrated solution lies on the difficulties in using the session initiation protocol (SIP) or SIP in combination with the real time streaming protocol (RTSP) for both the signaling and media control including so called trick functions that allow to manipulate media delivery by e.g. pausing and fast forwarding the content. This paper demonstrates fundamental scenarios and requirements towards a cooperative service delivery platform for the provisioning of IPTV services over IMS enabled next generation networks. As a result of that work a generic IMS-based cooperative service delivery platform is introduced

Quadruple Play - Session Management Enabler for Multimedia Streaming

Abstract: As the IMS represents an overlaying architecture, it is not limited to a single type of access network. However, the switching logic between different access networks is not provided by the IMS on its own. In fact this logic has to be integrated into a dedicated application server. Such an application server manages the transmission of multimedia streaming sessions over different access networks (UMTS, DVB-H, WiFi etc.) via different transmission schemes (unicast, multicast, broadcast). These multimedia streaming sessions are to be controlled within a stateful session management. This component has to be aware of both the content provider's delivery and the user's receiving behavior. Additionally the session management needs to be aware of the access network and the transmission scheme regarding the current user, network or content context to guarantee QoS and ensure the efficiency in providing this service delivery from network side. As a result, the session manager covers mobility aspects like session mobility and bearer mobility. This paper proposes and describes a session management enabler for a real time multimedia streaming architecture in the scope of quadruple play on top of the IP multimedia subsystem (IMS).

Service creation & delivery for SME based on SOA / IMS

Abstract: Modern telecommunication networks and classical roles of operators are subject to fundamental changes. Standardization bodies and the industry are specifying and integrating Next Generation Network (NGN) infrastructures and NGN services based on an all-IP paradigm. The IETF, ETSI, 3GPP, 3GPP2 and OMA are working on technological issues to enable services using Internet technology and Service Orientated Architectures (SOA).This paper reports about the German research project Multi-Access Modular-Services Framework (MAMS) funded by the German Federal Ministry of Education and Research (BMBF). It targets the access of Small and Medium Enterprises (SME) with an easy usable system, which allows creating and delivering new services without deep technical expertise.It focuses on the use of standardized telecommunications architectures and APIs for Network Abstraction to glue emerging telecommunication architectures with 3rd party services, the Internet and vice versa.

A Vertical Handover Architecture for End-to-End Service Optimization

Abstract: The present paper proposes integrating the media independent handover architecture (IEEE 802.21) into an IP multimedia subsystem (IMS) platform in order to deliver enhanced mechanisms to optimize the quality of the end-to-end service. The resulting architecture will complement the ability of the service delivery platforms - like IMS - to control and guarantee the network QoS and the cost parameters with a mechanism enabling them to collect information about the access networks available to the mobile terminals at any time and in any location. By correlating this information, it becomes possible to optimize the service quality through continuous adaptation of the multimedia session's parameters and service path towards identifying the best match between the momentary network and service context on one hand, and a "target" service profile negotiated by the users on the other hand.

A Network Controlled QoS Model over the 3GPP System Architecture Evolution

Abstract: Present network devices are able to access simultaneously services over various technologies e.g. UMTS, WLAN, WiMAX etc. each of these having different quality of service characteristics. Also for a specific service, different levels of quality could be offered depending on the client profile and on the momentary network capacities, giving the possibility of creating tiered access to resources. In order to enhance the network usability to these new conditions we propose an optimized, network driven QoS management and provisioning model. It is also considering a localization mechanism, doubled by a QoS control of the access networks. This paper focuses on a single operator scenario, which deploys multiple access technologies using an IMS signaled 3GPP System Architecture Evolution.

Evolution of Next Generation Networks towards an Integrated Platform for IMS-Based IPTV Services

Abstract: Next generation networks offer dedicated subsystems for each task to be fulfilled within the overall architecture defined in TISPAN NGN Release 1. There exist different subsystems for PSTN/ISDN emulation, streaming services and the 3GPP driven IP multimedia subsystem (IMS) which has been adapted to the NGN architecture. In NGN Release 2.0 IPTV shall be integrated into that architecture to support extended streaming services for next generation television. Current developments within ETSI TISPAN show two different approaches when speaking of the integration of IPTV services into the NGN: one IMS-based solution that relies on IMS/SIP signaling for new services and a non-IMS black box approach as an independent NGN subsystem. Our research activities are focused on the IMS-based activities and aim on the development of a reference architecture and on the service definition towards the now starting ETSI TISPAN standardization activities. This work shall introduce our architecture approach and evaluation based on precedent scenario and requirement analysis

IMS Playground in Pan-European Network of Testbeds; Benefits and Challenges

Abstract: The main idea for launching the FOKUS IMS Playground testbed in 2004 was to provide R&D for earlier IMS developments in order to validate existing and emerging IMS standards The IMS Playground was extended appropriately to be used on top of new access networks as well as to provide new seamless multimedia applications The FOKUS testbed originated from own developments as well as major industry players, and is being used by academic and industrial partners for prototyping new IMS related components, protocols, and applications The next target is to integrate FOKUS testbed in a Pan-European Network of testbeds in order to reach a broader community with the benefits of such a testbeds federation This paper describes the FOKUS experiences at running the IMS Playground, providing a look into administrative and technical issues that need consideration on integrating testbeds This view can be applied to run any kind of testbed The paper presents the descriptions of the issues from service/capabilities offer to test execution, as well as the intrinsic benefits and challenges

Mobile multimedia broadcasting vulnerability threats, attacks and security solutions

Abstract: The IP Multimedia Subsystem (IMS) has emerged as next generation value added communication services including mobile multimedia broadcasting, multimedia conferencing, push to talk and presence etc on top of all IP networks Offering multimedia streaming services across heterogeneous fixed and mobile networks have faced many challenges eg security, QoS, mobility and services management In this article our objective is to identity vulnerability threats and attacks, and to study existing potential solutions for mobile multimedia broadcasting The attacks possibilities are from multiple communication protocols suite ie Session Initiation Protocol (SIP) is used for session management, Diameter is used for authentication and authorization, Real-time Transport Protocol (RTP) & Real Time Streaming Protocol (RTSP) are used for media streaming on top of transport and IP infrastructure, therefore facing security challenges from three protocols domains We will also present extended security by developing Intrusion Detection and Prevention (IDP) System to secure IMS based Mobile Multimedia Broadcasting communication from Denial-of-Service (DoS) attacks

An Open IMS Testbed for exploring Wireless Service Evolution and Network Architecture Evolution towards SAE and LTE

Abstract: Modern telecommunication networks and classical roles of operators are subject to fundamental changes. Standardization bodies and Industry are specifying and integrating next generation network (NGN) infrastructures and NGN services based on an all IP paradigm. The Internet Engineering Task Force (IETF), European Telecommunications Standards Institute (ETSI), Third Generation Partnership Project (3GPP), 3GPP2 and Open Mobile Alliance (OMA) are working on technological issues to enable services using Internet technology and service orientated architectures (SOA). Furthermore, first thoughts on the architectural and bearer evolution of NGN is taking place under the notion of long term evolution (LTE) and system architecture evolution (SAE). This paper reports about our approach of extending the existing IP multimedia subsystem (IMS) Playground @ FOKUS towards a LTE/SAE testbed and two prototypic services, a single network agnostic voicemail application and a 3G circuit-switched to packet-switched handover scenario as a proof-of-concept for the environment.

The role of open ims testbeds in complex service delivery platforms

Abstract: Network convergence and the multimedia service provisioning platforms within next generation networks (NGN) are subjects of huge complexity and the required architecture is extremely expensive to implement. Network operators will find it difficult to commit the necessary capital expenditure unless the NGN architecture has been thoroughly tried and tested. To ensure early adoption of this convergence platform, low cost testbeds are needed to bring together various parties to research and develop the necessary architectures. The IP multimedia subsystem (IMS), defined by the 3rd Generation Partnership Project (3GPP) represents today the global service delivery platform (SDP) standard for providing multimedia applications in NGN. Knowing that the full potential of the IMS can only be revealed by the early non-discriminant provisioning of IMS know-how and related technologies to the different market players the Fraunhofer Institute FOKUS launched the "Open Source IMS Core" in November 2006, which is based on extensions to the SIP express router (SER) that cope with the SIP extensions specified by 3GPP. This paper describes the Open IMS Playground and the activities in progress and cooperation works between FOKUS and the University of Cape Town for establishing joint works on open issues within IMS research and development.

Enabling triple play services over NGN

Abstract: Triple play is the term used in the telecommunications market for describing the unified offering of three services: Television, Telephony (IP-based) and Internet Enabling triple play services within the concept of Next Generation Networks (NGN) over fixed and mobile access networks brings many research issues This demands design and development of new frameworks and testbeds for trialing these services The attention to triple play services has increased recently, and also enabling architectures like the IP Multimedia Subsystem (IMS) offer today possibilities to deliver triple play services with quality of service and mobility support However, IMS alone is not suited for offering these services, since it does not support multicast and broadcast transmission modes This paper presents the design of a framework that addresses these issues by integrating and testing the IMS with multicast and broadcast capabilities These efforts resulted in the creation of the Fraunhofer Institute FOKUS Media Interoperability Lab (MIL), which is as an open environment gathering all major IMS core components, and triple play toolkit originating from own developments as well as major industry players, which can be used by academic and industrial partners for early prototyping of new triple play services, related components, protocols, and applications An overview of the relevant technologies of the laboratory is presented and an implementation with measurement results is carried

Provisioning of an Open NGN/Triple Play Toolkit and Testbed

Abstract: Enabling next generation network to support multimedia streaming services across heterogeneous fixed and mobile networks challenges the developers to define a unified triple play framework solution. The IP multimedia subsystem (IMS) defined by the 3rd generation partnership projects (3GPP and 3GPP2) represents today a basis framework for a service delivery platform (SDP) for providing triple play services. Several approaches have already been introduced struggling with the need for an integrated solution based on the IMS core or the development of a separated subsystem. The Fraunhofer Institute FOKUS has launched the "Open IMS Playground" in July 2004 as part of the German 3G beyond national testbed. The IMS Playground has been extended recently as an open environment gathering all major IMS core components, and triple play toolkit originating from own developments as well as major industry players, which can be used by academic and industrial partners for early prototyping of new triple play services, related components, protocols, and applications. This paper introduces the relevant technologies and provides an overview of the "open NGN/triple play toolkit and testbed @ FOKUS".

Kommunikationsplattformen für maßgeschneiderte Dienste

Abstract: Die Telekommunikationswelt steht vor einem entscheidenden Umbruch. Waren die letzten Dekaden der Telekommunikation masgeblich durch Telefonie und sprachbasierte Einheitsmehrwertdienste gepragt, die festen und spater auch mobilen Netzbetreibern komfortable Einnahmen bescherten, zeigt heute sowohl „Voice over IP“ — also die Vermittlung von Sprache uber das Internet — als auch das so genannte Web 2.0 der Internetbasierten Multimedia-Anwendungen, wie Internettechnologien nachhaltig die (Tele)kommunikationslandschaft verandern. Sinkende Einnahmen durch immer gunstigere Sprachminuten und die steigende Verbreitung von festen und mobilen Internetzugangen, sowie die damit einhergehenden, zunehmend multimedialen Internetdienste fuhren zu der berechtigten Frage, wie zukunftig noch Geld in der Telekommunikationswelt zu verdienen ist. Die Konvergenz von Telekommunikation, Internet, Fernsehen und Unterhaltung — das so genannte Triple Play — zwingt dabei allerdings auch die anderen beteiligten Branchen zu dieser Fragestellung. „To bitpipe or not to bitpipe“ ist dabei die wesentliche Frage fur die traditionellen Netzbetreiber, d.h. zieht man sich auf die effiziente und durchaus profitable Bereitstellung von Netzzugangen zuruck, oder entwickelt man eigene Dienstkonzepte im Wettbewerb zur offenen Internetdienstwelt.