Validation of H-P2PSIP, a scalable solution for interoperability among different overlay networks

This paper reports the results of experiments from an implementation of H-P2PSIP, a hierarchical overlay architecture based on the ongoing work in the IETF P2PSIP Working Group. This architecture allows the exchange of information among different independent overlay networks through the use of a two-layer architecture based on super-peers and hierarchical identifiers. The validation of this proposal is based on a Linux based real implementation where we have used four different scenarios with 1,000 peers in order to perform different experiments. We have obtained results for different parameters such as routing performance (number of hops), delay, routing state (number of overlay routing entries) and bandwidth consumption.This research was supported in part by the European Commission Seventh Framework Programme under grant agreement n 25774 (TREND Network of Excellence), Comunidad de Madrid grant S-2009/TIC-1468 (MEDIANET project) and Spanish MICINN grant TEC2011-29688-C02-02 (eeCONTENT project).Publicad

H-P2PSIP: Interconnection of P2PSIP domains for Global Multimedia Services based on a Hierarchical DHT Overlay Network

The IETF P2PSIP WG is currently standardising a protocol for distributed mul- timedia services combining the media session functionality of SIP and the decentralised distribution and localisation of resources in peer-to-peer networks. The current P2PSIP scenarios only consider the infrastructure for the connectivity inside a single domain. This paper proposes an extension of the current work to a hierarchical multi-domain scenario: a two level hierarchical peer-to-peer overlay architecture for the interconnection of different P2PSIP domains. The purpose is the creation of a global decentralised multimedia services in enterprises, ISPs or community networks. We present a study of the Routing Performance and Routing State in the particular case of a two-level Distributed Hash Table Hierarchy that uses Kademlia. The study is supported by an analytical model and its validation by a peer-to-peer simulator.En prens

Analysis of relod.net, a basic implementation of the RELOAD protocol for peer-to-peer networks

Actas de: XI Jornadas de Ingeniería Telemática (JITEL 2013) celebradas en Granada, 28-30 Octubre 2013. La web del evento es: http://dtstc.ugr.es/jitel2013/#The P2PSIP Working Group is chartered to develop protocols and mechanisms for the use of SIP in distributed environments, thus minimizing the need for centralized servers. Under this premise, the RELOAD protocol was created, whose design was generalized to accept other applications with similar requirements, and which is currently in process of standardization by the IETF. In this paper, we present a basic implementation and an analysis of this protocol proposed standard, given the great interest displayed in recent years by the scientific and business community in issues related to peerto- peer networks. Later, we conduct several experiments in order to validate its correct operation in real scenarios and provide feedback in relation with the current specificationThis research was supported in part by the Comunidad de Madrid grant S-2009/TIC-1468 (MEDIANET project).Publicad

Design and evaluation of interconnecting structured peer-to-peer networks with a hierarchical topology

El tráfico en Internet está evolucionando continuamente. En el siglo XX, la mayor parte del tráfico en Internet soportado por los Proveedores de Servicios de Internet (ISP’s en terminología anglosajona) estaba relacionado con el tráfico web. Sin embargo, actualmente, el tráfico en Internet ha evolucionado drásticamente. La mayor parte del tráfico en Internet es tráfico Peer-to-Peer. Este cambio cambia completamente la situación en comparación con el siglo anterior, de ahí la relevancia del paradigma de las redes Peer-to-Peer. La adopción de las redes Peer-to-Peer está principalmente motivada por su uso en aplicaciones de compartición de ficheros pero la aplicación de las redes Peer-to-Peer no está sólo limitada al paradigma de compartición de ficheros. De hecho, las redes Peer-to-Peer son adecuadas para el desarrollo de cualquier servicio o aplicación distribuida ya que permiten almacenar información de manera distribuida entre un conjunto de nodos. Además, también permiten recuperar esa información cuando sea necesario. Una aplicación relevante basada en redes Peer-to-Peer es Skype la cual permite un servicio de VoIP entre varios millones de personas. Sin embargo, la interoperabilidad entre diferentes redes Peer-to-Peer no ha sido resuelta todavía. Cada red Peer-to-Peer define su propio mecanismo y su propio formato de paquete. Por lo tanto, sería deseable definir algún mecanismo que permita el intercambio de información entre diferentes redes Peer-to-Peer. Esta Tesis define un mecanismo que permite el intercambio de información entre diferentes redes Peer-to-Peer estructuradas, concretamente redes overlay basadas en DHT’s (Distributed Hash Tables). Este mecanismo está basado en un formato común de paquete, que asegura la interoperabilidad entre diferentes redes overlay, y en una arquitectura jerárquica. Esta arquitectura jerárquica está compuesta por dos niveles de jerarquáa. El nivel más bajo de la jerarquía está compuesto por las diferentes redes overlay que desean estar interconectadas. Cada una de estas redes overlay puede usar cualquier DHT, no existe ninguna restricción al respecto. Al menos un super-peer existe en cada una de estas redes overlay del nivel inferior; además, estos super-peer también participan en el nivel superior. Al nivel superior se le conoce como Red de Interconexión y está compuesto sólo por una red overlay. Su función es similar al servicio de DNS pero en el área de las redes Peer-to-Peer. En la Red de Interconexión se guarda la información de localización de cada uno de los super-peers y también el dominio o la overlay a la que representan. Por lo tanto, si un recurso de otra red quiere ser recuperado, un peer tiene que reenviar la petición a su super-peer. El super-peer consulta a la Red de Interconexión para localizar al super-peer que se hace cargo de la red destino donde se encuentra el recurso deseado y una vez que se localizar al super-peer, se le reenvía la petición. Finalmente, el super-peer en la red destino buscar el recurso deseado y lo envía de vuelta al peer que originó la petición. La arquitectura propuesta ha sido estudiada analíticamente para asegurar que el rendimiento es razonable en comparación con otras redes Peer-to-Peer. Además, la propuesta es validada con una herramienta de simulación para asegurar que las asunciones en el modelo analítico no afectan en un escenario más general. Finalmente, una implementación real sobre un entorno controlado es mostrada para demostrar la aplicabilidad y viabilidad de la propuesta. Los escenarios para las simulaciones y la verificación de la implementación han sido diseñados con especial cuidado para tener unas condiciones lo más cercanas posibles a escenarios reales.---------------------------------------------------------------------------------------------------------------------The traffic in the Internet is evolving continuously. In the 20th century, the most traffic supported by Internet Service Providers (ISP’s) was related with web traffic. However, nowadays, the traffic in the Internet has evolved drastically; now, most of the traffic in the Internet is Peer-to-Peer traffic. This fact changes completely the situation in comparison with the end of the previous century, thus the relevance of the Peer-to-Peer paradigm nowadays is evident. The adoption of Peer-to-Peer overlay networks was firstly motivated for its usage in file-sharing applications but the applicability of Peer-to-Peer overlay networks is not only limited to this kind of applications. In fact, Peer-to-Peer overlay networks are suitable for the development of any distributed application or service since they allow the allocation and retrieval of information in a distributed fashion among a set of nodes. However, each overlay network has its own structure and mechanisms to distribute the information among all nodes. Additionally, each Peer-to-Peer overlay network implementation usually defines its own packet format. Therefore, the interoperability among different overlay networks is not possible. This Thesis defines a mechanism to allow the exchange of information among different structured Peer-to Peer overlay networks, concretely DHT (Distributed Hash Table) overlay networks. This mechanism is based on both a common packet format, which assures the interoperability among different overlay networks, and on a hierarchical architecture. This hierarchical architecture has two levels of hierarchy. The lower level of the hierarchy is composed by the different overlay networks that want to be interconnected. Each one of these overlay networks can use any DHT overlay network with no restrictions. In addition, each overlay network in the lower level has at least one special peer, called super-peer. These super-peers are attached to the top level. This top level is named Interconnection Overlay and it is composed by just one overlay network. The purpose of super-peers is to route the queries among different overlay networks and they use the Interconnection Overlay to achieve this objective. In this Interconnection Overlay, the location information of each one of the superpeers and the overlay network represented by them are stored. Therefore, super-peers can forward the queries with the information stored in the Interconnection Overlay. If a resource placed in other overlay network wants to be obtained, a peer has to forward the query to its super-peer. The super-peer gets from the Interconnection Overlay the information about the super-peer that takes care of the destination overlay network and forwards this request. Finally, the super-peer in the destination overlay network looks for the desired resource and once is retrieved the answer is sent back to the requester. The proposed architecture is mathematically analysed to obtain is performance in term of hops and number of overlay routing entries in peers. Furthermore, the proposal is validated with a simulation tool to assure that the assumptions in the analytical model have been enough accurate. Finally, a real implementation over a controlled environment demonstrates the applicability and viability of the proposal and allows removing many of the original assumptions. The scenarios for the simulation analysis and the evaluation of the implementation have been designed carefully in order to define conditions as similar as possible to the real world

Security in peer-to-peer communication systems

P2PSIP (Peer-to-Peer Session Initiation Protocol) is a protocol developed by the IETF (Internet Engineering Task Force) for the establishment, completion and modi¿cation of communication sessions that emerges as a complement to SIP (Session Initiation Protocol) in environments where the original SIP protocol may fail for technical, ¿nancial, security, or social reasons. In order to do so, P2PSIP systems replace all the architecture of servers of the original SIP systems used for the registration and location of users, by a structured P2P network that distributes these functions among all the user agents that are part of the system. This new architecture, as with any emerging system, presents a completely new security problematic which analysis, subject of this thesis, is of crucial importance for its secure development and future standardization. Starting with a study of the state of the art in network security and continuing with more speci¿c systems such as SIP and P2P, we identify the most important security services within the architecture of a P2PSIP communication system: access control, bootstrap, routing, storage and communication. Once the security services have been identi¿ed, we conduct an analysis of the attacks that can a¿ect each of them, as well as a study of the existing countermeasures that can be used to prevent or mitigate these attacks. Based on the presented attacks and the weaknesses found in the existing measures to prevent them, we design speci¿c solutions to improve the security of P2PSIP communication systems. To this end, we focus on the service that stands as the cornerstone of P2PSIP communication systems¿ security: access control. Among the new designed solutions stand out: a certi¿cation model based on the segregation of the identity of users and nodes, a model for secure access control for on-the-¿y P2PSIP systems and an authorization framework for P2PSIP systems built on the recently published Internet Attribute Certi¿cate Pro¿le for Authorization. Finally, based on the existing measures and the new solutions designed, we de¿ne a set of security recommendations that should be considered for the design, implementation and maintenance of P2PSIP communication systems.Postprint (published version

Integrating Wireless Sensor Networks and Mobile Ad-hoc NETworks for enhanced value-added services

In some situations where the standard telecommunication infrastructure is not available, Mobile Ad hoc NETworks (MANETs) can be deployed to provide the required communication. These networks are established "on the fly" without a need for prior communication organization and are composed of autonomous mobile devices, such as cell phones, PDAs or laptops. In similar conditions, such as in emergency response operations, integrating MANETs and Wireless Sensor Networks (WSNs) can notably enhance the MANET participant's end-user experience. WSNs sense and aggregate ambient information, such as physiological, environmental or physical data related to a nearby phenomenon. The integration, which provides end-user availability to WSN required information, is feasible via gateways. However, when the ambient information collected by WSNs is intended for applications residing in MANETs, centralized and fixed gateways are not practicably feasible. This is mainly due to ad-hoc nature, lack of centralized control and constraints on the end-user devices that are used in MANETs. These devices are usually limited in power and capacity and cannot host centralized gateways. In this thesis we exploit the integration of WSN and MANET in order to provide novel value-added services which enhance the end-user experience of MANET participants. Motivating scenarios are introduced, background information is presented, requirements are derived and the state of the art regarding the integration of WSN with existing networks, including MANETs, is evaluated. Based on the evaluation, none of the existing solutions satisfies all of our derived requirements. Therefore, we propose an overall two-level overlay architecture to integrate WSNs (with mobile sinks) and MANETs. This architecture is based on the distributed gateway and applications which form the P2P overlays. Overlays are application-layer networks which are created on top of the exiting MANET. To interconnect gateway and application overlays we derive corresponding requirements and evaluate the existing approaches. Since none of these approaches fulfills all of our requirements, we propose protocols, mechanisms and design corresponding modules for the interconnection of overlays. Finally we refine our overall architecture based on the interconnection aspects. As a proof of concept, we implement a prototype for the inter-overlay information exchange. This implementation is based on SIP extensions and uses two existing P2P middlewares. We also simulate our prototype using Oversim simulation tool and collect experimental results. Based on these results, we can see that our architecture is a valid and promising approach for interconnecting different P2P overlays and can be deployed to provide the overall solution for WSN and MANET integrated system

Service composition based on SIP peer-to-peer networks

Today the telecommunication market is faced with the situation that customers are requesting for new telecommunication services, especially value added services. The concept of Next Generation Networks (NGN) seems to be a solution for this, so this concept finds its way into the telecommunication area. These customer expectations have emerged in the context of NGN and the associated migration of the telecommunication networks from traditional circuit-switched towards packet-switched networks. One fundamental aspect of the NGN concept is to outsource the intelligence of services from the switching plane onto separated Service Delivery Platforms using SIP (Session Initiation Protocol) to provide the required signalling functionality. Caused by this migration process towards NGN SIP has appeared as the major signalling protocol for IP (Internet Protocol) based NGN. This will lead in contrast to ISDN (Integrated Services Digital Network) and IN (Intelligent Network) to significantly lower dependences among the network and services and enables to implement new services much easier and faster. In addition, further concepts from the IT (Information Technology) namely SOA (Service-Oriented Architecture) have largely influenced the telecommunication sector forced by amalgamation of IT and telecommunications. The benefit of applying SOA in telecommunication services is the acceleration of service creation and delivery. Main features of the SOA are that services are reusable, discoverable combinable and independently accessible from any location. Integration of those features offers a broader flexibility and efficiency for varying demands on services. This thesis proposes a novel framework for service provisioning and composition in SIP-based peer-to-peer networks applying the principles of SOA. One key contribution of the framework is the approach to enable the provisioning and composition of services which is performed by applying SIP. Based on this, the framework provides a flexible and fast way to request the creation for composite services. Furthermore the framework enables to request and combine multimodal value-added services, which means that they are no longer limited regarding media types such as audio, video and text. The proposed framework has been validated by a prototype implementation

An Overlay Gateway for the Integration of IP Multimedia Subsystem and Mobile Sink Based-Wireless Sensor Networks

RÉSUMÉ D'une part les Réseaux de Capteurs (WSN par ses sigles en anglais) constituent un domaine de recherche qui a reçu beaucoup d'attention de la part de la communauté scientifique grâce à ses avantages en différents domaines. Chaque réseau est généralement conçu à partir de périphériques de petite taille appelés capteurs qui peuvent capter, effectuer des calculs et communiquer entre eux. De plus, inclure des stations de base mobiles dans les réseaux de capteurs sans fils s'est avéré utile dans une large gamme de scénarios puisque ces derniers permettent d'améliorer la durée de vie globale du réseau et d'augmenter la capacité de transmission de données. D'autre part, le sous-système IP Multimédia (IMS) vise à fournir un accès aux réseaux cellulaires à l'ensemble des services Internet. Il s'agit d'une surcouche de contrôle implantée sur une couche IP dont les objectifs sont de fournir et maintenir une qualité de service (QoS) donnée, un schéma de chargement équitable et des services intégrés; le tout en utilisant des interfaces standards. Combiner les fonctionnalités d‟IMS et l‟ensemble d'informations contextuelles capturées par les stations de base des réseaux de capteurs sans fils ouvre la porte à une nouvelle gamme de services multimédias. Cette dissertation propose une architecture de surcouche pour l'intégration des IMS avec les réseaux de capteurs sans fils. Le service "présence" sert de point d'entrée au domaine des IMS. La passerelle, qui constitue le coeur de notre architecture, est une couche de recouvrement construite sur les mêmes téléphones mobiles qui agissent également en tant que canaux mobiles, publicateurs / écouteurs de présence et périphériques utilisateurs. ----------ABSTRACT On one hand, Wireless Sensor Networks (WSNs) are a research area that has been gaining attention from the research community. They are made up of small scale devices called sensors that can sense, compute and communicate. Moreover, including mobile sinks in WSNs has shown to be useful in a wide range of scenarios since they can improve the overall network lifetime and increase data capacity. On the other hand, the IP Multimedia Subsystem (IMS) aims to provide cellular access to all Internet services. It is an overlay control layer on top of an IP layer whose goals is based in provisioning of Quality of Service (QoS), a fair charging scheme and integrated services through standard interfaces. Combining the capabilities of IMS with the rich set of contextual information captured by mobile sink WSNs opens the door to a wide range of novel multimedia services. This dissertation proposes an overlay architecture for the integration of IMS with mobile sink-based WSN. The Presence service is used as entry point to the IMS world. The gateway which is the heart of our architecture is an overlay built on top of the very same mobile phones that act as mobile sinks, presence publishers / watchers, and end-user devices