An interoperable and secure architecture for internet-scale decentralized personal communication

Interpersonal network communications, including Voice over IP (VoIP) and Instant Messaging (IM), are increasingly popular communications tools. However, systems to date have generally adopted a client-server model, requiring complex centralized infrastructure, or have not adhered to any VoIP or IM standard. Many deployment scenarios either require no central equipment, or due to unique properties of the deployment, are limited or rendered unattractive by central servers. to address these scenarios, we present a solution based on the Session Initiation Protocol (SIP) standard, utilizing a decentralized Peer-to-Peer (P2P) mechanism to distribute data. Our new approach, P2PSIP, enables users to communicate with minimal or no centralized servers, while providing secure, real-time, authenticated communications comparable in security and performance to centralized solutions.;We present two complete protocol descriptions and system designs. The first, the SOSIMPLE/dSIP protocol, is a P2P-over-SIP solution, utilizing SIP both for the transport of P2P messages and personal communications, yielding an interoperable, single-stack solution for P2P communications. The RELOAD protocol is a binary P2P protocol, designed for use in a SIP-using-P2P architecture where an existing SIP application is modified to use an additional, binary RELOAD stack to distribute user information without need for a central server.;To meet the unique security needs of a fully decentralized communications system, we propose an enrollment-time certificate authority model that provides asserted identity and strong P2P and user-level security. In this model, a centralized server is contacted only at enrollment time. No run-time connections to the servers are required.;Additionally, we show that traditional P2P message routing mechanisms are inappropriate for P2PSIP. The existing mechanisms are generally optimized for file sharing and neglect critical practical elements of the open Internet --- namely link-level security and asymmetric connectivity caused by Network Address Translators (NATs). In response to these shortcomings, we introduce a new message routing paradigm, Adaptive Routing (AR), and using both analytical models and simulation show that AR significantly improves message routing performance for P2PSIP systems.;Our work has led to the creation of a new research topic within the P2P and interpersonal communications communities, P2PSIP. Our seminal publications have provided the impetus for subsequent P2PSIP publications, for the listing of P2PSIP as a topic in conference calls for papers, and for the formation of a new working group in the Internet Engineering Task Force (IETF), directed to develop an open Internet standard for P2PSIP

Design and implementation of a hierarchical SIP-based peer-to-peer network

Peer-to-peer (P2P) has gained popularity in Internet due to the increased number of users and distributed services such as file sharing and voice calls over IP (VoIP). Currently, the most popular P2P networks store information pertaining to its resources in a distributed manner using Distributed Hash Tables (DHT). In this type of networks, the peers are deterministically positioned and resources are also allocated to each peer for indexing in a deterministic manner. This paper presents a new hierarchical SIP based P2P network. A pure SIP solution was used because we believe that an open solution such as SIP can facilitate the creation of new types of services and permit the facilitated integration of different services. A two level hierarchy is used and is aimed towards the improvement of network efficiency where peers can move dynamically from one layer to another according to its available resources. In addition to this, the proposed implementation architecture allows the independence of the underlying DHT algorithms. The proposed architecture was implemented and tested in a realistic scenario which was created inside a Linux cluster. The DHT algorithms, Chord and EpiChord, were also implemented and used to index resources in either flat or hierarchical networks. Results indicate that the proposed two-layer hierarchy significantly improves the P2P overlay performance while in the presence of peers with limitations.(undefined

Simulating a Mobile Peer-to-Peer Network

Vertaisverkkosovellukset (P2P-sovellukset) ovat saapuneet kannettaviin laitteisiin, kun laitteiden prosessoriteho, tallennuskapasiteetti sekä matkapuhelinverkkojen kaistanleveys on kasvanut. Perinteiset P2P-sovellukset ovat liian raskaita mobiilikäyttöön. Uusia, kevyempiä vertaisverkkoprotokollia tarvitaan mahdollistamaan P2P-sovellusten toiminta mobiiliympäristössä. P2P Session Initiation Protocol (P2PSIP) on kehitteillä oleva protokolla, jonka avulla SIP protokollan yhteydenmuodostus toteutetaan ilman palvelimia. Tämän työn tavoitteena oli simuloinnin avulla tutkia Resource Location and Delivery (RELOAD) vertaisprotokollaa käyttävää P2PSIP päällysverkkoa. Tarkastelun kohteena olivat erityisesti kaistanleveyden tarve, hakujen kustannukset sekä hakujen onnistuminen. Myös solmujen päällysverkkoon liittymisestä ja päällysverkosta poistumisesta aiheutuvat vaikutukset tuloksiin olivat mielenkiinnon kohteina. Tämä työ vertailee kahden hajautetun tiivistetaulualgoritmin, Chordin ja Kademlian, suorituskykyä. Simulaatiot on suoritettu C++ ohjelmointikielellä toteutetulla OverSimpäällysverkkosimulaattorilla. Tämä työ osoittaa, että 2G-matkapuhelinverkon kaistanleveys on riittävä P2PSIPpäällysverkon tarpeisiin. Kademliaa käytettäessä kaistanleveys on suurempi, mutta hakujen viive pienempi ja onnistumisprosentti suurempi kuin Chordia käytettäessä. Tulokset osoittavat, että tässä työssä käytetyillä parametreilla hakujen onnistumisprosentti on monille sovelluksille liian alhainen eikä mahdollista niille tyydyttävää palvelun laatua.Peer-to-peer (P2P) applications have become available for portable devices as the processing power and the storage capacity of the devices as well as the network bandwidth have increased. The traditional P2P applications have been considered too heavy for mobile usage. New, lightweight P2P protocols are needed for mobile P2P applications. P2P Session Initiation Protocol (P2PSIP) is a protocol under development that provides the session establishment functions of SIP in a serverless fashion. The main objective of this thesis was to simulate a P2PSIP overlay network operating with Resource Location And Delivery (RELOAD) peer protocol and study its bandwidth consumption, lookup overhead and lookup success rate. The effect of churn, the process of nodes arriving to the overlay and leaving it, on these results was also one of our concerns. We study if this kind of network is applicable to be implemented on top of current mobile telephone networks. This study compares the performance of two distributed hash table (DHT) algorithms, Chord and Kademlia. The simulations were carried out with OverSim overlay network simulator implemented in the C++ programming language. This study shows that P2PSIP network's bandwidth usage is low enough to operate on top of the 2G mobile telephone networks. Kademlia uses more bandwidth than Chord but it has a shorter lookup delay and a higher lookup success rate than Chord. The results show that with the parameter settings used in our study the lookup success rates are in general too low for many applications to give them a satisfying quality of service

Prospects of peer-to-peer SIP for mobile operators

Tämän diplomityön tarkoituksena on esitellä kehitteillä oleva Peer-to-Peer Session Initiation Protocol (P2PSIP), jonka avulla käyttäjät voivat itsenäisesti ja helposti luoda keskenään puhe- ja muita multimediayhteyksiä vertaisverkko-tekniikan avulla. Lisäksi tarkoituksena on arvioida P2PSIP protokollan vaikutuksia ja mahdollisuuksia mobiilioperaattoreille, joille sitä voidaan pitää uhkana. Tästä huolimatta, P2PSIP:n ei ole kuitenkaan tarkoitus korvata nykyisiä puhelinverkkoja. Työn alussa esittelemme SIP:n ja vertaisverkkojen (Peer-to-Peer) periaatteet, joihin P2PSIP-protokollan on suunniteltu perustuvan. SIP mahdollistaa multimedia-istuntojen luomisen, sulkemisen ja muokkaamisen verkossa, mutta sen monipuolinen käyttö vaatii keskitettyjen palvelimien käyttöä. Vertaisverkon avulla käyttäjät voivat suorittaa keskitettyjen palvelimien tehtävät keskenään hajautetusti. Tällöin voidaan ylläpitää laajojakin verkkoja tehokkaasti ilman palvelimista aiheutuvia ylläpito-kustannuksia. Mobiilioperaattorit ovat haasteellisen tilanteen edessä, koska teleliikennemaailma on muuttumassa yhä avoimemmaksi. Tällöin operaattoreiden asiakkaille aukeaa mahdollisuuksia käyttää kilpailevia Internet-palveluja (kuten Skype) helpommin ja tulevaisuudessa myös itse muodostamaan kommunikointiverkkoja P2PSIP:n avulla. Tutkimukset osoittavat, että näistä uhista huolimatta myös operaattorit pystyvät näkemään P2PSIP:n mahdollisuutena mukautumisessa nopeasti muuttuvan teleliikennemaailman haasteisiin. Nämä mahdollisuudet sisältävät operaattorin oman verkon optimoinnin lisäksi vaihtoehtoisten ja monipuolisempien palveluiden tarjoamisen asiakkailleen edullisesti. Täytyy kuitenkin muistaa, että näiden mahdollisuuksien toteuttamisten vaikutusten ei tulisi olla ristiriidassa operaattorin muiden palveluiden kanssa. Lisäksi tulisi muistaa, että tällä hetkellä keskeneräisen P2PSIP-standardin lopullinen luonne ja ominaisuudet voivat muuttaa sen vaikutuksia.The purpose of this thesis is to present the Peer-to-Peer Session Initiation Protocol (P2PSIP) being developed. In addition, the purpose of this thesis is to evaluate the impacts and prospects of P2PSIP to mobile operators, to whom it can be regarded as a threat. In P2PSIP, users can independently and easily establish voice and other multimedia connections using peer-to-peer (P2P) networking. However, P2PSIP is not meant to replace the existing telephony networks of the operators. We start by introducing the principles of SIP and P2P networking that the P2PSIP is intended to use. SIP enables to establish, terminate and modify multimedia sessions, but its versatile exploitation requires using centralized servers. By using P2P networking, users can decentralize the functions of centralized servers by performing them among themselves. This enables to maintain large and robust networks without maintenance costs resulted of running such centralized servers. Telecommunications market is transforming to a more open environment, where mobile operators and other service providers are challenged to adapt to the upcoming changes. Subscribers have easier access to rivalling Internet-services (such as Skype) and in future they can form their own communication communities by using P2PSIP. The results show that despite of these threats, telecom operators can find potential from P2PSIP in concurrence in adaptation to the challenges of the rapidly changing telecom environment. These potential roles include optimization of the network of the operator, but as well roles to provide alternative and more versatile services to their subscribers at low cost. However, the usage of P2PSIP should not conflict with the other services of the operator. Also, as P2PSIP is still under development, its final nature and features may change its impacts and prospects