http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
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The Session Initiation Protocol (SIP) working group is chartered to
continue the development of SIP, currently specified as proposed
standard RFC 2543. SIP is a text-based protocol, similar to HTTP and
SMTP, for initiating interactive communication sessions between users.
Such sessions include voice, video, chat, interactive games, and
virtual reality. The main work of the group involves bringing SIP from
proposed to draft standard, in addition to specifying and developing
proposed extensions that arise out of strong requirements. The SIP
working group will concentrate on the specification of SIP and its
extensions, and will not explore the use of SIP for specific
environments or applications. It will, however respond to
general-purpose requirements for changes to SIP provided by other
working groups, including the SIPPING working group, when those
requirements are within the scope and charter of SIP.
Throughout its work, the group will strive to maintain the basic model
and architecture defined by SIP. In particular:
1. Services and features are provided end-to-end whenever possible.
2. Extensions and new features must be generally applicable, and not
applicable only to a specific set of session types.
3. Simplicity is key.
4. Reuse of existing IP protocols and architectures, and integrating
with other IP applications, is crucial.
SIP was first developed within the Multiparty Multimedia Session
Control (MMUSIC) working group, and the SIP working group will continue
to maintain active communications with MMUSIC. This is particularly
important since the main MIME type carried in SIP messages, the Session
Description Protocol (SDP), specified in RFC 2327, is developed by