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The support for this SIP version has been discon­tinued!

The support for this SIP version has been discon­tinued!

The support for this SIP version has been discon­tinued!
The support for this SIP version has been discon­tinued!
The support for this SIP version has been discon­tinued!
These symbols label different SIP version on this Wiki

SIP = Session Initiation Protocol


In telecommunication, "telephony" encompasses the general use of equipment to provide voice communication over distances. Traditional telephone systems were originally based on the analogue system of physical connection via fixed cables and transmission via electrical pulses. Both digital systems and new connectivity media (fibre, satellite) extended the scope and reliability of telephony systems, such that very few analogue systems are still in use.

Internet Protocol (IP) telephony differs from digital telephony in that it transmits digitised voice data via networks originally built for data transmission, not for voice transmission. At its basic level, IP is a set of rules that allows computer networks to communicate with other, with IP telephony building on these rules. IP is based on internet protocols, not telephony protocols. This means that IP networks use the same rules that govern the World Wide Web, not those that govern standard circuit-switched PABX telephony.

SIP is an extension of the IP protocol. Essentially, SIP is the future standard for communications of all kinds via a data network and its appeal lies largely in its simplicity: SIP sets up, handles and ends "sessions" over IP networks. A session could be a simple two-way telephone call or it could be a collaborative multi-media conference session. The ability to establish these sessions means that a host of innovative services become possible, such as voice-enriched e-commerce, web page click-to-dial and Instant Messaging.

Over the last couple of years, the Voice over IP community has adopted SIP as its protocol of choice for signalling and SIP is now a specification of the International Engineering Task Force (IETF). Until the IETF's SIP standard was embraced, VoIP phone systems were in danger of proprietary vendor lock-in. Gradually, SIP is evolving from the prestigious protocols it resembles -- the Web's Hyper Text Transfer Protocol (HTTP) formatting protocol and the Simple Mail Transfer Protocol (SMTP) email protocol -- into a powerful emerging standard.

Like the Internet, SIP is easy to understand, extend and implement. In telephony this means that all communication is managed by the network, from a simple phone call through to voice-enriched eCommerce, web page click-to-dial and instant messaging. SIP users may locate and contact one another-regardless of media content or number of participants. SIP extends the open-standards spirit of the Internet to messaging, enabling disparate computers, phones, televisions and software to communicate with each other.


Das Session Initiation Protocol (SIP) ist ein Netzprotokoll zum Aufbau von Kommunikationsverbindungen aller Art. Dabei können alle möglichen Kommunikationsgeräte wie Telefone, Computer und PDA einbezogen werden und gleichzeitig ganz unterschiedliche Medien wie Sprache und Video zum Einsatz kommen. Neben Applikationen für Telephonie und Video Conferencing, Instant Messaging und Presence ist auch Mobility ein herausragendes Anwendungsfeld.

Mit einer SIP basierten Architektur können die Möglichkeiten der Vernetzung über IP für alle Nutzer voll ausgeschöpft werden, auch über mehrere Kontinente hinweg. Auf diese Weise können Firmen ihre Lösungen und Anwendungen durchgängig allen Mitarbeitern zur Verfügung stellen und eine einheitliche technische Infrastruktur verwirklichen.

Als ein von der Internet Engineering Task Force (IETF) initiiertes Protokoll steht SIP für schnelle Innovation und bietet gleichzeitig die wichtigen Standards für das nahtlose Zusammenspiel der Lösungen im Netz.

SIP relevant articles / SIP-relevante Artikel

See also / Siehe auch