Orientador: Leonardo de Souza Mendes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-18T16:50:00Z (GMT). No. of bitstreams: 1 Panhan_AndreMarcelo_D.pdf: 1974417 bytes, checksum: 984825f99aaa2e172e580c7197422517 (MD5) Previous issue date: 2011 / Resumo: As cidades digitais compõem um movimento emergente que visa a criação de ambientes virtuais, os quais surgem como uma alternativa para potencializar a promoção de comunidades e regiões de modo a complementar a organização das cidades reais. Elas representam ambientes com capacidade cognitiva e criativa, construídos a partir de competências individuais e sistemas de informação que operam sobre os espaços físicos, institucionais e digitais das cidades. Duas questões principais guiaram este estudo: o desenvolvimento de ambientes inovadores para cidades e a interoperabilidade de sistemas distribuídos das cidades digitais. Após uma introdução sobre o significado de cidades digitais, será apresentada a arquitetura proposta para a criação de um ambiente computacional para cidades digitais, baseado em um middleware peer-topeer (P2P). A arquitetura proposta para cidades digitais neste trabalho proporciona escalabilidade, interoperabilidade, independência de plataformas e fomento da produção comercial, cultural e tecnológica / Abstract: Digital cities comprise an emerging movement that aims to create virtual environments, which arise as an alternative to potentiate the promotion of communities and regions to complement the organization of real cities. They represent environments with cognitive ability and creative, constructed from individual skills and information systems that operate on the physical, institutional and digital spaces from cities. Two main questions guided this study: the development of innovative environments for cities and interoperability of distributed systems of digital cities. After an introduction on the meaning of digital cities, will be presented the proposed architecture to create a computational environment for digital cities, based on a peer-to-peer (P2P) middleware. The proposed architecture for digital cities in this work provides scalability, interoperability, platform independence and promoting commercial production, cultural and technological / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica

Grades computacionais oportunistas utilizam recursos ociosos de máquinas compartilhadas para executar aplicações que necessitam de um alto poder computacional e/ou trabalham com grandes quantidades de dados. Mas a execução de aplicações paralelas computacionalmente intensivas em ambientes dinâmicos e heterogêneos, como grades computacionais oportunistas, é uma tarefa difícil. Máquinas podem falhar, ficar inacessíveis ou passar de ociosas para ocupadas inesperadamente, comprometendo a execução de aplicações. Um mecanismo de tolerância a falhas que dê suporte a arquiteturas heterogêneas é um importante requisito para estes sistemas. Neste trabalho, analisamos, implementamos e avaliamos um mecanismo de tolerância a falhas baseado em checkpointing para aplicações paralelas em grades computacionais oportunistas. Este mecanismo permite o monitoramento de execuções e a migração de aplicações entre nós heterogêneos da grade. Mas além da execução, é preciso gerenciar e armazenar os dados gerados e utilizados por estas aplicações. Desejamos uma infra-estrutura de armazenamento de dados de baixo custo e que utilize o espaço livre em disco de máquinas compartilhadas da grade. Devemos utilizar somente os ciclos ociosos destas máquinas para armazenar e recuperar dados, de modo que um sistema de armazenamento distribuído que as utilize deve ser redundante e tolerante a falhas. Para resolver o problema do armazenamento de dados em grades oportunistas, projetamos, implementamos e avaliamos o middleware OppStore. Este middleware provê armazenamento distribuído e confiável de dados, que podem ser acessados de qualquer máquina da grade. As máquinas são organizadas em aglomerados, que são conectados por uma rede peer-to-peer auto-organizável e tolerante a falhas. Dados são codificados em fragmentos redundantes antes de serem armazenados, de modo que arquivos podem ser reconstruídos utilizando apenas um subconjunto destes fragmentos. Finalmente, para lidar com a heterogeneidade dos recursos, desenvolvemos uma extensão ao protocolo de roteamento em redes peer-to-peer Pastry. Esta extensão adiciona balanceamento de carga e suporte à heterogeneidade de máquinas ao protocolo Pastry. / Opportunistic computational grids use idle resources from shared machines to execute applications that need large amounts of computational power and/or deal with large amounts of data. But executing computationally intensive parallel applications in dynamic and heterogeneous environments, such as opportunistic grids, is a daunting task. Machines may fail, become inaccessible, or change from idle to occupied unexpectedly, compromising the application execution. A fault tolerance mechanism that supports heterogeneous architectures is an important requisite for such systems. In this work, we analyze, implement and evaluate a checkpointing-based fault tolerance mechanism for parallel applications running on opportunistic grids. The mechanism monitors application execution and allows the migration of applications between heterogeneous nodes of the grid. But besides application execution, it is necessary to manage data generated and used by those applications. We want a low cost data storage infrastructure that utilizes the unused disk space of grid shared machines. The system should use the machines to store and recover data only during their idle periods, requiring the system to be redundant and fault-tolerant. To solve the data storage problem in opportunistic grids, we designed, implemented and evaluated the OppStore middleware. This middleware provides reliable distributed storage for application data, which can be accessed from any machine in the grid. The machines are organized in clusters, connected by a self-organizing and fault-tolerant peer-to-peer network. During storage, data is codified into redundant fragments, allowing the reconstruction of the original file using only a subset of those fragments. Finally, to deal with resource heterogeneity, we developed an extension to the Pastry peer-to-peer routing substrate, enabling heterogeneity-aware load-balancing message routing.

The main aim of this master's thesis is to implement a common, secure and peer-to-peer communication system. The system has ability to automatically establish and run a secure end-to-end connection. It has this ability even if a network address translator is in the way to the destination system, without need of any explicit configuration of this translator. The security procedures of this system are in a transparent manner masked from individual applications, which had to solve this challenge in their own way. A responsibility for a security is delegate to an application-independent subsystem working within the core of an operating system. The security of this subsystem is based on capturing the outbound and inbound IP packets and their authentication and encryption. The system was successfully implemented in MS Windows XP operating system, in programming language C++. Transfer rate of communication tunnel in different network bandwidth speeds was measured. Result shows, that in the case of use the system on standard PC sold nowadays is practically no decrease of the transfer rate in comparison to a common channel.

This document provides information about Cisco NetFlow technology and its usage to protect networks from different types of attacks. Part of the document is a summary of common security risks in term of their detection on network and transport layer. There are specified characteristics of NetFlow data containing samples of security risks. On the basis of these characteristics, an application for detection these risks is designed and implemented.

Aus der Einleitung: "Neben „klassischen“ virtuellen Gemeinschaften, die einen gemeinsamen Netzort für die Interaktion benutzen und die auf technischer Ebene vornehmlich durch den Einsatz von Client-Server-Architekturen gekennzeichnet sind, lassen sich Gemeinschaftsformen identifizieren, deren Ursprung in vollkommen dezentralen Peer-to-Peer (P2P)-Netzen liegt. Diese P2P-Gemeinschaften haben in einigen Anwendungsgebieten wie dem Filesharing großen Erfolg [SF02]."

Um die ständig wachsenden Anforderungen zur Übertragung von Live Video Streams im Internet zu erfüllen werden kosteneffektive und resourceneffiziente Lösungen benötigt. Eine adäquate Lösung bietet die Peer-to-Peer (P2P) Streaming Architektur an, welche bereits heute in unterschiedlichsten Systemen zum Einsatz kommt. Solche Systeme erfordern von der Streaming Quelle nur moderate Bandbreiten, da die Nutzer (bzw. Peers) ihre eigene Bandbreite zur Verbreitung des Streams einbringen. Dazu werden die Peers oberhalb der Internetarchitektur zu einem Overlay verbunden. Das geplante Verlassen, sowie der ungewollte Absturz von Peers (genannt Churn) kann das Overlay schädigen und den Empfang einiger Peers unterbrechen. Weitaus kritischer sind Angriffe auf die Verfügbarkeit des Systems indem relevante Knoten des Overlays von Angreifern attackiert werden, um die Verteilung des Streams gezielt zu stören. Um Overlays zu konstruieren, die robust gegenüber Churn sind, nutzen so genannte pull-basierte P2P Streaming Systeme eine Mesh Topologie um jeden Peer über mehrere Pfade mit der Quelle zu verbinden. Peers fordern regelmäßig Teile des Videos, sog. Chunks, von ihren Partnern im Overlay an. Selbst wenn einige Partner plötzlich nicht mehr im System verfügbar sind kann ein Peer alle Chunks von den verbleibenden Nachbarn beziehen. Um dies zu ermöglichen tauschen Peers regelmäßig sog. Buffer Maps aus. Diese kleinen Pakete enthalten Informationen über die Verfügbarkeit von Chunks im Puffer eines Peers. Um dadurch entstehende Latenzen und den zusätzlichen Mehraufwand zu reduzieren wurden hybride Systeme entwickelt. Ein solches System beginnt pull-basiert und formt mit der Zeit einen Baum aus einer kleinen Untermenge aller Peers um Chunks ohne explizite Anfrage weiterzuleiten. Unglücklicherweise sind sowohl pull-basierte, als auch hybride Systeme anfällig gegenüber Denial-of-Service Angriffen (DoS). Insbesondere fehlen Maßnahmen zur Abschwächung von DoS Angriffen auf die Partner der Quelle. Die genannten Angriffe werden weiterhin dadurch erleichtert, dass die Identität der Quelle-nahen Knoten akkurat aus den ausgetauschten Buffer Maps extrahiert werden kann. Hybride Systeme sind außerdem anfällig für Angriffe auf den zugrundeliegenden Baum. Aufgrund der schwerwiegenden Auswirkungen von DoS Angriffen auf pull-basierte, sowie hybride Systeme stellen wir drei Gegenmaßnahmen vor. Zuerst entwickeln wir das Striping Schema zur Abschwächung von DoS Angriffen auf die Partner der Quelle. Hierbei werden Peers dazu angeregt ihre Chunk-Anfragen an unterschiedliche Partner zu senden. Als zweites entwickeln wir das SWAP Schema, welches Peers dazu bringt proaktiv ihre Partner zu wechseln um Angreifer daran zu hindern die Quellenahe zu identifizieren. Als drittes entwickeln wir RBCS, einen widerstandsfähigen Baum zur Abschwächung von DoS Angriffen auf hybride Systeme. Da bisher kein Simulator für die faire Evaluation von P2P-basierten Live Video Streaming Algorithmen verfügbar war, entwickeln wir OSSim, ein generalisiertes Simulations-Framework für P2P-basiertes Video Streaming. Des weiteren entwickeln wir etliche Angreifermodelle sowie neuartige Resilienzmetriken on OSSim. Ausgiebige Simulationsstudien zeigen, dass die entwickelten Schemata signifikant die Widerstandsfähigkeit von pull-basierten und hybriden Systemen gegenüber Churn und DoS Angriffen erhöhen. / The constantly growing demand to watch live videos over the Internet requires streaming systems to be cost-effective and resource-efficient. The Peer-to-Peer (P2P) streaming architecture has been a viable solution with various deployed systems to date. The system only requires a modest amount of bandwidth from the streaming source, since users (or peers) contribute their bandwidth to disseminate video streams. To enable this, the system interconnects peers into an overlay. However, churn–meaning the leaving and failing of peers–can break the overlay, making peers unable to receive the stream. More severely, an adversary aiming to sabotage the system can attack relevant nodes on the overlay, disrupting the stream delivery. To construct an overlay robust to churn, pull-based P2P streaming systems use a mesh topology to provide each peer with multiple paths to the source. Peers regularly request video chunks from their partners in the overlay. Therefore, even if some partners are suddenly absent, due to churn, a peer still can request chunks from its remaining partners. To enable this, peers periodically exchange buffer maps, small packets containing the availability information of peers’ video buffers. To reduce latency and overhead caused by the periodic buffer map exchange and chunk requests, hybrid systems have been proposed. A hybrid system bootstraps from a pull-based one and gradually forms a tree backbone consisting of a small subset of peers to deliver chunks without requests. Unfortunately, both pull-based and hybrid systems lack measures to mitigate Denial-of-Service (DoS) attacks on head nodes (or the source’s partners). More critically, they can be identified accurately by inferring exchanged buffer maps. Furthermore, hybrid systems are vulnerable to DoS attacks on their backbones. Since DoS attacks can badly affect both pull-based and hybrid systems, we introduce three countermeasures. First, we develop the striping scheme to mitigate DoS attacks targeting head nodes. The scheme enforces peers to diversify their chunk requests. Second, to prevent attackers from identifying head nodes, we develop the SWAP scheme, which enforces peers to proactively change their partners. Third, we develop RBCS, a resilient backbone, to mitigate DoS attacks on hybrid systems. Since a simulator for a fair evaluation is unavailable so far, we develop OSSim, a general-purpose simulation framework for P2P video streaming. Furthermore, we develop several attacker models and novel resilience metrics in OSSim. Extensive simulation studies show that the developed schemes significantly improve the resilient of pull-based and hybrid systems to both churn and DoS attacks.

In this thesis I describe my research activities and results of the last 4 years. I also provide an outlook and guidelines on how to proceed with our project, that we named SEDNS - Security-Enhanced Domain Name System. This project’s ambitions are to complement DNS, the Domain Name System, in a way that allows us to keep using it in the future. The main reason for this strategy is, that it has proven to be difficult to change any part of the Internet infrastructure, such as parts of the protocols stack or well established Internet authorities, like ICANN or IANA. The main problems of DNS are twofold. (1) The DNS protocol does not contain any measures to prevent data from being tampered with. (2) Furthermore, it is difficult to configure DNS correctly since most of the configuration is done within the DNS data itself, e.g., delegating authority. It is well known that DNS problems lead to reduced availability of Internet-based services in many different ways. In this thesis, I present four main results. All of them contribute to improvements and deeper understanding of DNS’ dependability issues. First, I discuss, how well established cryptographic tools can be used to enhance DNS’ security without getting into the same problems that prevent DNSSEC from being globally deployed. These problems are explained as well. This is an important topic for the Internet and DNS community, since at the moment most of the protocol improvements are connected to DNSSEC. Second, I thoroughly discuss the technique that was used in the recent years to overcome any problems related to client-server architectures, i.e., peer-to-peer systems. Such solutions have been proposed to improve DNS’ availability and reduce configuration effort. I show, that those systems do not keep up with the expectations, neither as client side tools nor as server infrastructure replacement. To reach this conclusion, a novel DHT scheme has been developed. The evaluation of it is shown as well. Third, results of our DNS data mining show that it is useful to improve the quality of DNS data and therefore, to protect clients from malicious or erroneous information. And fourth, an outlook is presented, which combines all the results of the first three points to suggest an architecture that indeed can improve our supply with DNS data, omitting the shortcomings of the classical client-server-architecture and its peer-to-peer replacements. Note, that although the development of future DNS standards and protocols is subject to political struggle, e.g., on whether or not an international organization should maintain the root zone instead of the USA, this thesis focuses only on technical aspects. / In dieser Dissertation beschreibe ich meine Forschungsaktivitäten und Ergebnisse der letzten 4 Jahre. Ich gebe auch einen Ausblick und Hinweise, wie unser Project, das wir SEDNS - Security-Enhanced Domain Name System genannt haben, fortgesetzt werden sollte. Die Ambitionen dieses Projektes sind, DNS, das Domain Name System, zu in einer Art und Weise zu erweitern, die es uns erlauben soll, dieses System auch in der Zukunft weiter zu benutzen. Der Hauptgrund für diese Strategie ist, dass es sich in der Vergangenheit als schwierig erwiesen hat, Teile der Internet-Infrastruktur, wie zum Beispiel Teile des Protokollstapels oder gut etablierte Internet-Behörden wie ICANN oder IANA, zu ändern bzw. auszutauschen. Daher wollen wir nicht versuchen, DNS komplett zu ersetzen. DNS hat zwei Hauptprobleme: (1) Das DNS Protokoll bietet keinerlei Möglichkeiten, Daten vor Verfälschung zu schützen, und (2) es ist schwierig, DNS korrekt zu konfigurieren, weil ein Großteil der Konfiguration direkt innerhalb der DNS Daten selbst stattfindet, wie zum Beispiel die Delegation von Verantwortungsbereichen, und diese oft nicht global konsistent und korrekt sind. Diese Probleme sind umso bedeutender, weil es allgemein bekannt ist, dass DNS Probleme auf verschiedene Art und Weisen zu reduzierter Verfügbarkeit von wichtigen Internet-basierten Diensten führen. In dieser Arbeit präsentiere ich vier Hauptergebnisse. Zuerst diskutiere ich, wie gut etablierte kryptographische Werkzeuge benutzt werden können um die Sicherheit von DNS zu verbessern, ohne dabei auf dieselben Probleme zu stoßen, die DNSSEC davon abhalten, weltweit benutzt zu werden. Diese Probleme werden dabei erläutert. Es handelt sich dabei um ein wichtiges Thema für die Internet- und DNS-Community, weil im Moment die meisten Weiterentwicklungen des DNS Protokolls mit DNSSEC zusammenhängen. Als zweites diskutiere ich im Detail die Technik, die in den vergangenen Jahren benutzt wurde um Probleme beliebiger Client-Server Anwendungen zu überwinden: Peer-to-Peer Systeme. Derartige Lösungen wurden vorgeschlagen, um DNS' Verfügbarkeit zu verbessern und Konfigurationsaufwand zu reduzieren. Ich zeige allerdings, dass solche Lösungen nicht die in sie gesetzten Erwartungen erfüllen, weder als Client-seitige Tools noch als Ersatz für die Server-Infrastruktur. Um diesen Schluss zu ziehen, wurde ein neues, auf die Bedürfnisse von DNS zugeschnittenes DHT Schema entwickelt und evaluiert im Vergleich zu DNS und existierenden Systemen. Als drittes werden DNS Data Mining Ergebnisse präsentiert, die zeigen, wie sinnvoll es ist, die Qualität der DNS Daten zu verbessern, und somit Clients vor bösartigen oder fehlerhaften Informationen zu schützen. Als viertes wird ein Ausblick präsentiert, der die Ergebnisse der vorherigen drei Punkte kombiniert und eine Architektur vorschlägt, die unsere Versorgung mit DNS Daten tatsächlich verbessern kann und die Nachteile der klassischen Client-Server-Architektur und ihrer Peer-to-Peer Nachfolger vermeidet. Zu beachten ist, dass obwohl die Entwicklung zukünftiger DNS Standards und Protokolle Gegenstand politischer Konflikte ist, z.B. darüber ob anstelle der USA eine internationale Organisation die Root-Zone verwalten sollte, diese Arbeit nur auf die technischen Aspekte ausgerichtet ist.

Internet of Things utvecklas och växer konstant. Det blir allt vanligare att applikationer och enheter kopplas samman via nätverk. En av teknikerna som används för att trådlöst sammankoppla enheter är Bluetooth Low Energy. Preferenser för kvaliteten i en kommunikation kan variera. Det är därför viktigt att utföra prestandamätningar för att veta vilka fördelar och nackdelar en nätverksteknik har.  Detta examensarbete handlar om prestandamätningar vid datasändningar mellan mobila enheter och trådlösa sensorer, och övervakning av parametrar som fås under mätningarna. En metod med monitoreringspaket inspirerad från tidigare forskning, utformades och implementerades i ett system för Bluetooth Low Energy, vilken därefter har utvärderats.  Resultatet blev att två system skapades som visade dataförluster, fördröjningsvariation och genomströmning, löpande på en mobil enhet. Det ena systemet använde metoden med monitoreringspaket. Det andra systemet använde en egengjord metod som gjorde mätningar med hög precision, men som ställde högre krav på funktioner och prestanda på sensornoden, och på den mobila enheten. Experiment med hjälp av systemen utfördes och resulterande värden analyserades. / Internet of Things develops and grows constantly. It becomes increasingly common that applications and units are connected through a network. One of the technologies used for wirelessly linking together units is Bluetooth Low Energy. Preferences for the quality of a connection can vary. It is therefore important to conduct measurements of performance in order to know advantages and disadvantages that a networking technology has.  This thesis is about measurements of performance during data transfers between mobile devices and wireless sensors, as well as monitoring parameters that are given during the measurements. One method using monitoring packets inspired from previously made research, were designed and implemented in a system for Bluetooth Low Energy, which was then evaluated. The result was that two systems were created that presented data loss, delay variation and throughput, continuously on a mobile device. One system used the method with monitoring packets. The other system used a self-made method which made measurements with high precision, but that places higher demands on functions and performance of the sensor node, and on the mobile device. Experiments were conducted by using the systems and resulting values were analyzed.

Der interuniversitäre Bachelor-Studiengang Energy Efficiency and Englishes hat die Zielsetzung, dass Studierende zum einen ingenieurs- und technikwissenschaftliche Kompetenzen und zum anderen kultur- und sprachwissenschaftliche Kompetenzen erwerben und somit für den Arbeitsmarkt bessere Voraussetzungen mitbringen. Ziel des Ko- Pi-Projektes war es, die Module „Einführung Energietechnik“ und „Applied Linguistics“ besser an die Bedürfnisse der Studierenden anzupassen und gleichzeitig die Verknüpfung von technikwissenschaftlichen mit sprachwissenschaftlichen Kompetenzen zu schaffen, um diese praktisch im Unterricht anzuwenden und weiterzuentwickeln.

Cette thèse propose une nouvelle architecture Peer-to-Peer pour l’établissement de sessions SIP (Session Initiation Protocol) sur les réseaux ad hoc. SIP est un protocole con¸cu à l’origine sur un modèle centralisé est n’est pas nativement adapté aux réseaux mobiles ad hoc (MANET) en raison de leurs caractéristiques inhérentes de mobilité. Nous avons ciblé nos études sur un mécanisme de lookup distribué Peer-to-Peer (P2P) tolérant aux fautes, même en cas de mobilité des noeuds du réseau. Cette thèse s’articule autour de quatre principales contributions: Nous introduisons le concept de Structured Mesh Overlay Network (SMON) : un overlay P2P sur MANET permettant d’effectuer des lookups de ressources rapides dans un environnement ad hoc. SMON utilise une architecture cross layer design basée sur une Distributed Hash Table (DHT) utilisant directement les informations de routage OLSR. Cette architecture cross layer permet d’optimiser les performances du réseau overlay lors d’un changement de topologie du réseau. La seconde contribution, SIPMON, est un overlay SIP sur réseau SMON. Sa particularité est d’utiliser un DHT pour distribuer les identifiants d’objet SIP dans le réseau overlay SMON. Les expérimentations menées prouvent que cette approche garantit une durée de découverte SIP constante et permet un établissement de session plus rapide entre deux usagers sur réseau ad hoc. SIPMON ne s’applique cependant qu’à un réseau MANET isolé. Notre troisième contribution SIPMON+ permet un interfonctionnement de plusieurs overlays SIPMON connectés à Internet. SIPMON+ unifie donc les overlays de réseau et permet de joindre un client SIP qu’il soit localisé sur un réseau ad hoc ou sur l’internet. De plus, SIPMON+ permet une continuité de service sans couture lors du passage entre un réseau MANET et un réseau d’infrastructure. Notre prototype a démontré que les performances de temps d’établissement d’appel SIPMON+ étaient meilleures que pour l’approche concurrente MANEMO (MANET for Network Mobility). Le scénario d’usage principal est la fourniture de services de communication multimédia d’urgence rapidement déployables en cas de catastrophe majeure. Nous avons développé un prototype SIPMON+ totalement fonctionnel de service de communication P2P multimédia. Ce prototype a été expérimenté en situation réelle de catastrophe. Notre prototype sans infrastructure a donné de biens meilleurs résultats que MANEMO en termes de temps de déploiement, de taux de perte de paquets et de temps d’établissement d’appel. / This work presents a novel Peer to Peer (P2P) framework for Session Initiation Protocol (SIP) on Mobile Ad Hoc Network (MANET). SIP is a client-server model of computing which can introduce a single point of failure problem. P2P SIP addresses this problem by using a distributed implementation based on a P2P paradigm. However, both the traditional SIP and P2P SIP architectures are not suitable for MANETs because they are initially designed for infrastructured networks whose most nodes are static. We focus on distributed P2P resource lookup mechanisms for SIP which can tolerate failures resulting from the node mobility. Our target application is SIP-based multimedia communication in a rapidly deployable disaster emergency network. To achieve our goal, we provide four contributions as follows. The first contribution is a novel P2P lookup architecture based on a concept of P2P overlay network called a Structured Mesh Overlay Network (SMON). This overlay network enables P2P applications to perform fast resource lookups in the MANET environment. SMON utilizes a cross layer design based on the Distributed Hashing Table (DHT) and has direct access to OLSR routing information. Its cross layer design allows optimizing the overlay network performance during the change of network topology. The second contribution is a distributed SIP architecture on MANET providing SIP user location discovery in a P2P manner which tolerates single-point and multiple-point of failures. Our approach extends the traditional SIP user location discovery by utilizing DHT in SMON to distribute SIP object identifiers over SMON. It offers a constant time on SIP user discovery which results in a fast call setup time between two MANET users. From simulation and experiment results, we find that SIPMON provides the lowest call setup delay when compared to the existing broadcast-based approaches. The third contribution is an extended SIPMON supporting several participating MANETs connected to Internet. This extension (SIPMON+) provides seamless mobility support allowing a SIP user to roam from an ad hoc network to an infrastructured network such as Internet without interrupting an ongoing session. We propose a novel OLSR Overlay Network (OON), a single overlay network containing MANET nodes and some nodes on the Internet. These nodes can communicate using the same OLSR routing protocol. Therefore, SIPMON can be automatically extended without modifying SIPMON internal operations. Through our test-bed experiments, we prove that SIPMON+ has better performance in terms of call setup delay and handoff delay than MANET for Network Mobility (MANEMO). The fourth contribution is a proof-of-concept and a prototype of P2P multimedia communication based on SIPMON+ for post disaster recovery missions. We evaluate our prototype and MANEMO-based approaches through experimentation in real disaster situations (Vehicle to Infrastructure scenarios). We found that our prototype outperforms MANEMO-based approaches in terms of call setup delay, packet loss, and deployment time.