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SIP/IN Interworking

Document Charter SIP/IN Interworking WG (sin)
Title SIP/IN Interworking
Last updated 2003-12-10
State Approved
WG State Concluded
IESG Responsible AD (None)
Charter edit AD (None)
Send notices to (None)


The SIP/IN Interworking (SIN) BOF is intended to determine whether a
working item on SIP/IN interworking is needed in the IETF, and, if so,
whether the relevant work is to be carried in an existing working group
or a new working group is to be created.

SIP/IN Interworking is considered here for the purpose of utilizing the
existing Intelligent Network solutions in setting up an
'IP_Host-to-Phone' call. The solution of this problem is essential to
the industry in order to re-use the existing applications in the IP
telephony environment: most telephony applications (800, PSTN VPN,
credit card calling, to name only a few) are based on IN. It is
essential then to re-use them in the IP telephony environment. The
proposed architecture employs the Software Switch (soft switch), which

appears to the PSTN (in this case, the IN service control point) as a
"normal" PSTN switch; it appears to the IP network as a SIP Server.

Thus, the soft switch must translate certain SIP messages into
appropriate Intelligent Network Application Part (INAP) queries to
service control; conversely, responses and instructions from the
control must be translated into (sequences of) SIP messages. In
particular, 1) IN Call Model must be interpreted for the SIP-based IP
telephony environment;

2) IN messages must be mapped into (sequences of) SIP messages and vice

3) IN parameters must be mapped into existing SIP parameters (or
relevant SIP extensions must be defined) and vice versa

It is proposed that this work be carried jointly between the IETF and
ITU-T IN questions."