Session Initiation Protocol (SIP)

SIP was initially developed by the IETF Multiparty Multimedia Session Control (MMUSIC) working group, from Sept. 1999 in the IETF SIP working group^†.

SIP is a text-based protocol, similar to HTTP and SMTP, for initiating interactive communication sessions between users. Sessions include: voice, video, chat, interactive games, and virtual reality.

SIP working group’s charter: “… to maintain the basic model and architecture defined by SIP. In particular:

Services and features are provided end-to-end whenever possible^‡.
Extensions and new features must be generally applicable, and not applicable only to a specific set of session types.
Simplicity is key.
Reuse of existing IP protocols and architectures, and integration with other IP applications, is crucial.

^†Now the Session Initiation Protocol Core (sipcore) working group - see https://datatracker.ietf.org/wg/sipcore/ Links to an external site.

^‡ The use of end-to-end control is the exact opposite of the centralized control in traditional telecommunication networks.

Slide Notes

Multiparty Multimedia Session Control (mmusic) Working Group, Webpage, http://www.ietf.org/html.charters/mmusic-charter.html Links to an external site.

Transcript

[slide113] If not, we're going to leap into SIP, the Session Initiation Protocol. It's a text-based protocol, it looks tremendously like HTTP. It's designed to be able to support different services, end-to-end services. It is supposed to be simple. It is also designed to be very extensible.