545 research outputs found

    Design and Analysis of IP-Multimedia Subsystem (IMS)

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    Preventing Distributed Denial-of-Service Attacks on the IMS Emergency Services Support through Adaptive Firewall Pinholing

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    Emergency services are vital services that Next Generation Networks (NGNs) have to provide. As the IP Multimedia Subsystem (IMS) is in the heart of NGNs, 3GPP has carried the burden of specifying a standardized IMS-based emergency services framework. Unfortunately, like any other IP-based standards, the IMS-based emergency service framework is prone to Distributed Denial of Service (DDoS) attacks. We propose in this work, a simple but efficient solution that can prevent certain types of such attacks by creating firewall pinholes that regular clients will surely be able to pass in contrast to the attackers clients. Our solution was implemented, tested in an appropriate testbed, and its efficiency was proven.Comment: 17 Pages, IJNGN Journa

    Serviços multimédia multicast de próxima geração

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    Mestrado em Engenharia ElectrĂłnica e TelecomunicaçÔesUma das mais recentes conquistas na evolução mĂłvel foi o 3G, permitindo o acesso a serviços multimĂ©dia com qualidade de serviço assegurada. No entanto, a tecnologia UMTS, tal como definida na sua Release ’99, Ă© apenas capaz de transmitir em modo unicast, sendo manifestamente ineficiente para comunicaçÔes multimĂ©dia almejando grupos de utilizadores. A tecnologia IMS surge na Release 5 do 3GPP que começou a responder jĂĄ a algumas necessidades, permitindo comunicaçÔes sobre IP oferecendo serviços Internet a qualquer momento e em qualquer lugar sobre tecnologias de comunicação mĂłveis fornecendo pela primeira vez sessĂ”es multimĂ©dia satisfatĂłrias. A Release 6 por sua vez trouxe a tecnologia MBMS que permite transmissĂ”es em broadcast e multicast para redes mĂłveis. O MBMS fornece os serviços de aplicaçÔes multimĂ©dia que todos estavam Ă  espera, tanto para os utilizadores como para os prestadores de serviços. O operador pode agora fazer uso da tecnologia existente aumentando todo o tipo de benefĂ­cios no serviço prestado ao cliente. Com a possĂ­vel integração destas duas tecnologias passa a ser possĂ­vel desenvolver serviços assentes em redes convergentes em que os conteĂșdos sĂŁo entregues usando tecnologias unicast, multicast ou broadcast. Neste contexto, o principal motivo deste trabalho consiste essencialmente em fazer uso dos recursos da rede terminando com o desperdĂ­cio dos mesmos e aumentando a eficiĂȘncia dos serviços atravĂ©s da integração das tecnologias IMS e MBMS. O trabalho realizado começa com o estudo do estado da arte das telecomunicaçÔes mĂłveis com referĂȘncia Ă s tecnologias referidas, seguindo-se a apresentação da possĂ­vel integração IMS-MBMS e terminando com o projecto de uma plataforma de demonstração que no futuro possa ser uma implementação de serviço multimĂ©dia multicast. O objectivo principal Ă© mostrar os benefĂ­cios de um serviço que era normalmente executado em unicast relativamente ao modo multicast, fazendo uso da nova convergĂȘncia de tecnologias IMS e MBMS. Na conclusĂŁo do trabalho sĂŁo referidas as vantagens do uso de portadoras multicast e broadcast, tendo como perspectiva de que este trabalho possa ser um ponto de partida para um novo conjunto de serviços poupando recursos de rede e permitindo uma eficiĂȘncia considerĂĄvel em serviços inovadores.3G is bang up to date in the mobile phone industry. It allows access to multimedia services and gives a guarantee of quality of service. The UMTS technology, defined in 3GPP Release ’99, provides an unicast transmission, but it is completely inefficient when it comes to multimedia group communications. The IMS technology first appeared in Release 5 that has already started to consider the interests of the clients. It provides communications over IP, offering Internet services anytime, anywhere on mobile communication technologies. Also, it offers for the first time satisfactory multimedia sessions. On the other hand, Release 6 gave rise to the MBMS technology that provides broadcast and multicast transmissions for mobile networks. The MBMS provides multimedia applications services that everyone was waiting, including users and service providers. Now the operator makes use of existing technology in order to provide better costumer services. The possible integration of these two technologies will contribute to develop services based on converged networks in which contents are delivered through the unicast, multicast or broadcast technologies. Therefore, the objective of this work is basically to make use of network resources avoiding wastes and improving customer services through the integration of the IMS and the MBMS technologies. The executed work starts with the mobile telecommunications state of the art with reference to the referred technologies, followed by the IMS-MBMS convergence presentation and finishing with the proposal for implementation of a service platform that can be used for a multimedia multicast service. The main point is to show the benefits of a service that has been normally executed in unicast mode over the multicast mode, making use of the new IMS and MBMS technologies integration. To closure the work it is referred the advantages to use multicast and broadcast bearers, with the perspective that this work could be a starting point to a new set of services, saving network resources and allowing for innovate services a considerable efficency

    Optimizing IETF multimedia signaling protocols and architectures in 3GPP networks : an evolutionary approach

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    Signaling in Next Generation IP-based networks heavily relies in the family of multimedia signaling protocols defined by IETF. Two of these signaling protocols are RTSP and SIP, which are text-based, client-server, request-response signaling protocols aimed at enabling multimedia sessions over IP networks. RTSP was conceived to set up streaming sessions from a Content / Streaming Server to a Streaming Client, while SIP was conceived to set up media (e.g.: voice, video, chat, file sharing, 
) sessions among users. However, their scope has evolved and expanded over time to cover virtually any type of content and media session. As mobile networks progressively evolved towards an IP-only (All-IP) concept, particularly in 4G and 5G networks, 3GPP had to select IP-based signaling protocols for core mobile services, as opposed to traditional SS7-based protocols used in the circuit-switched domain in use in 2G and 3G networks. In that context, rather than reinventing the wheel, 3GPP decided to leverage Internet protocols and the work carried on by the IETF. Hence, it was not surprise that when 3GPP defined the so-called Packet-switched Streaming Service (PSS) for real-time continuous media delivery, it selected RTSP as its signaling protocol and, more importantly, SIP was eventually selected as the core signaling protocol for all multimedia core services in the mobile (All-)IP domain. This 3GPP decision to use off-the-shelf IETF-standardized signaling protocols has been a key cornerstone for the future of All-IP fixed / mobile networks convergence and Next Generation Networks (NGN) in general. In this context, the main goal of our work has been analyzing how such general purpose IP multimedia signaling protocols are deployed and behave over 3GPP mobile networks. Effectively, usage of IP protocols is key to enable cross-vendor interoperability. On the other hand, due to the specific nature of the mobile domain, there are scenarios where it might be possible to leverage some additional “context” to enhance the performance of such protocols in the particular case of mobile networks. With this idea in mind, the bulk of this thesis work has consisted on analyzing and optimizing the performance of SIP and RTSP multimedia signaling protocols and defining optimized deployment architectures, with particular focus on the 3GPP PSS and the 3GPP Mission Critical Push-to-Talk (MCPTT) service. This work was preceded by a detailed analysis work of the performance of underlying IP, UDP and TCP protocol performance over 3GPP networks, which provided the best baseline for the future work around IP multimedia signaling protocols. Our contributions include the proposal of new optimizations to enhance multimedia streaming session setup procedures, detailed analysis and optimizations of a SIP-based Presence service and, finally, the definition of new use cases and optimized deployment architectures for the 3GPP MCPTT service. All this work has been published in the form of one book, three papers published in JCR cited International Journals, 5 articles published in International Conferences, one paper published in a National Conference and one awarded patent. This thesis work provides a detailed description of all contributions plus a comprehensive overview of their context, the guiding principles beneath all contributions, their applicability to different network deployment technologies (from 2.5G to 5G), a detailed overview of the related OMA and 3GPP architectures, services and design principles. Last but not least, the potential evolution of this research work into the 5G domain is also outlined as well.Els mecanismes de SenyalitzaciĂł en xarxes de nova generaciĂł es fonamenten en protocols de senyalitzaciĂł definits per IETF. En particular, SIP i RTSP sĂłn dos protocols extensibles basats en missatges de text i paradigma peticiĂł-resposta. RTSP va ser concebut per a establir sessions de streaming de continguts, mentre SIP va ser creat inicialment per a facilitar l’establiment de sessions multimĂšdia (veu, vĂ­deo, xat, comparticiĂł) entre usuaris. Tot i aixĂ­, el seu Ă mbit d’aplicaciĂł s’ha anat expandint i evolucionant fins a cobrir virtualment qualsevol tipus de contingut i sessiĂł multimĂšdia. A mesura que les xarxes mĂČbils han anat evolucionant cap a un paradigma “All-IP”, particularment en xarxes 4G i 5G, 3GPP va seleccionar els protocols i arquitectures destinats a gestionar la senyalitzaciĂł dels serveis mĂČbils presents i futurs. En un moment determinat 3GPP decideix que, a diferĂšncia dels sistemes 2G i 3G que fan servir protocols basats en SS7, els sistemes de nova generaciĂł farien servir protocols estandarditzats per IETF. Quan 3GPP va començar a estandarditzar el servei de Streaming sobre xarxes mĂČbils PSS (Packet-switched Streaming Service) va escollir el protocol RTSP com a mecanisme de senyalitzaciĂł. Encara mĂ©s significatiu, el protocol SIP va ser escollit com a mecanisme de senyalitzaciĂł per a IMS (IP Multimedia Subsystem), l’arquitectura de nova generaciĂł que substituirĂ  la xarxa telefĂČnica tradicional i permetrĂ  el desplegament de nous serveis multimĂšdia. La decisiĂł per part de 3GPP de seleccionar protocols estĂ ndards definits per IETF ha representat una fita cabdal per a la convergĂšncia del sistemes All-IP fixes i mĂČbils, i per al desenvolupament de xarxes NGN (Next Generation Networks) en general. En aquest context, el nostre objectiu inicial ha estat analitzar com aquests protocols de senyalitzaciĂł multimĂšdia, dissenyats per a xarxes IP genĂšriques, es comporten sobre xarxes mĂČbils 3GPP. Efectivament, l’Ășs de protocols IP Ă©s fonamental de cara a facilitar la interoperabilitat de solucions diferents. Per altra banda, hi ha escenaris a on Ă©s possible aprofitar informaciĂł de “context” addicional per a millorar el comportament d’aquests protocols en al cas particular de xarxes mĂČbils. El cos principal del treball de la tesi ha consistit en l’anĂ lisi i optimitzaciĂł del rendiment dels protocols de senyalitzaciĂł multimĂšdia SIP i RTSP, i la definiciĂł d’arquitectures de desplegament, amb Ăšmfasi en els serveis 3GPP PSS i 3GPP Mission Critical Push-to-Talk (MCPTT). Aquest treball ha estat precedit per una feina d’anĂ lisi detallada del comportament dels protocols IP, TCP i UDP sobre xarxes 3GPP, que va proporcionar els fonaments adequats per a la posterior tasca d’anĂ lisi de protocols de senyalitzaciĂł sobre xarxes mĂČbils. Les contribucions inclouen la proposta de noves optimitzacions per a millorar els procediments d’establiment de sessions de streaming multimĂšdia, l’anĂ lisi detallat i optimitzaciĂł del servei de PresĂšncia basat en SIP i la definiciĂł de nous casos d’Ășs i exemples de desplegament d’arquitectures optimitzades per al servei 3GPP MCPTT. Aquestes contribucions ha quedat reflectides en un llibre, tres articles publicats en Revistes Internacionals amb Ă­ndex JCR, 5 articles publicats en ConferĂšncies Internacionals, un article publicat en CongrĂ©s Nacional i l’adjudicaciĂł d’una patent. La tesi proporciona una descripciĂł detallada de totes les contribucions, aixĂ­ com un exhaustiu repĂ s del seu context, dels principis fonamentals subjacents a totes les contribucions, la seva aplicabilitat a diferents tipus de desplegaments de xarxa (des de 2.5G a 5G), aixĂ­ una presentaciĂł detallada de les arquitectures associades definides per organismes com OMA o 3GPP. Finalment tambĂ© es presenta l’evoluciĂł potencial de la tasca de recerca cap a sistemes 5G.Postprint (published version

    Evaluating Extensions to IMS Session Setup for Multicast-based Many-to-Many Services

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    Telecommunication networks are converging towards an all-IP paradigm that integrates a broad set of value-added services. In this context, the IP Multimedia Subsystem (IMS) is being developed by the 3GPP as a key element to achieve the convergence. Additionally, multiparty services are nowadays acquiring an increasing interest from the industry. In this respect, network multicast provides a cost-effective solution to deliver these services to the user. Nevertheless, although network multicast is being considered as an enabler for one-to-many services (e.g. IPTV) in the IMS, the specifications for many-to-many services still follow a unicast approach (e.g. push-to-talk and conference). This paper describes extensions to the session control procedures in the IMS, to support multicast based multi-user services. The idea was first described in a prior work, but this paper presents enhancements to provide a comprehensive solution and to improve the grade of service (GOS) perceived by the users. In addition, the GOS achieved by the proposal is evaluated. First, the bandwidth utilization for the multicast-based multi-user services is analyzed and compared against the unicast scenario. Next, the GOS is evaluated using an analytical approach, by obtaining the mathematical expressions for the session and user plane setup delays. Finally, the GOS is also evaluated using an experimental approach, and the results are compared with values recommended by the ITU-T
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