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

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