PINT

This document contains the specification of the PINT Service Protocol 1.0, which defines a protocol for invoking certain telephone services from an IP network. These services include placing basic calls, sending and receiving faxes, and receiving content over the telephone. The protocol is specified as a set of enhancements and additions to the SIP 2.0 and SDP protocols.

The PINT 1.0 status registration and indication scheme uses three new methods; SUBSCRIBE, UNSUBSCRIBE, and NOTIFY. These are used to allow a PINT client to register an interest in (or “subscribe” to) the status of a service request, to indicate that a prior interest has lapsed (i.e “unsubscribe” from the status), and for the server to return service indications. The state machine of SUBSCRIBE/UNSUBSCRIBE is identical to that of INVITE/BYE; just as INVITE signals the beginning and BYE signals the end of participation in a media session, SUBSCRIBE signals the beginning and UNSUBSCRIBE signals the end of participation in a monitoring session. During the monitoring session, NOTIFY messages are sent to inform the subscriber of a change in session state or disposition.