Peer-to-peer SIP (P2P-SIP) is an implementation of a distributed

voice over Internet Protocol Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet t ...

(VoIP) or

instant messaging Instant messaging (IM) technology is a type of online chat allowing real-time text transmission over the Internet or another computer network. Messages are typically transmitted between two or more parties, when each user inputs text and trigge ...

communications application using a

peer-to-peer Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the network. They are said to form a peer-to-peer ...

(P2P) architecture in which session control between communication end points is facilitated with the Session Initiation Protocol (SIP).

SIP in a P2P architecture

In a pure peer-to-peer application architecture no central servers are required, whereas traditional SIP telephony networks have relied on using centrally deployed and managed SIP servers, in analogy to the centralized switching architecture of the public switched telephone network (PSTN).RFC 3261, ''SIP: Session Initiation Protocol'', J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, E. Schooler, The Internet Society (June 2002) P2P application design can improve scalability and survivability in the event of central network outages. The Session Initiation Protocol is in principle a client-server protocol, however it has been described in analogy to the P2P relationship, called a ''dialog'', which is defined by a unique combination of SIP protocol parameters (To-tag, From-tag, Call-ID). Both endpoints of a communication session implement a user-agent server and a user-agent client, which enables any two user agents to communicate directly with one another without the mediation of another a central switching system. SIP also provides facilities of registering (REGISTER request) the network location of a user agent with other SIP elements and subscription (SUBSCRIBE request) and notification (NOTIFY request) features for event tracking between user agents. Based on these inherent SIP features it is possible to construct a peer-to-peer network of SIP nodes. In another approach, SIP over P2P, the SIP location service is replaced by conventional P2P overlay networking approach, such as the

OverSim OverSim is an OMNeT++-based open-source simulation framework for overlay and peer-to-peer networks, developed at the Institute of Telematics, Karlsruhe Institute of Technology, Germany. The simulator contains several models for structured (e.g. ...

framework. In this model, the overlay network is used for service or node discovery and rendezvous. The search key in such a mechanism is the Uniform Resource Identifier (URI) of a user agent. This URI requires resolution to a particular device or

Uniform Resource Locator A Uniform Resource Locator (URL), colloquially termed as a web address, is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it. A URL is a specific type of Uniform Resource Identifi ...

(URL) that must be performed in real time. P2P-SIP systems may employ structured peer-to-peer approaches, as well as unstructured peer-to-peer architectures.

Standards

The

Internet Engineering Task Force The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and a ...

(IETF) is conducting a working group (P2PSIP) that develops standards-track specifications for P2P-SIP. This effort is based on using the ''REsource LOcation And Discovery (RELOAD) Base Protocol'' a peer-to-peer (P2P) signaling protocol for use on the Internet. The P2P signaling protocol provides the network nodes that form an overlay network with abstract storage, messaging, and security services.

References

External links

The OverSim home page

P2PSIP demonstrator based on P2PNS
* * * A code library for P2P over SIP
Sip2Peer project
{{DEFAULTSORT:P2p-Sip Peer-to-peer computing Voice over IP