Minutes of the PSTN/Internet Interworking (pint) WG Meeting on December 10, 1997 Reported by S. Bellovin (AT&T Labs-Research) smb@research.att.com and I. Faynberg (Bell Labs, Lucent Technologies) faynberg@bell-labs.com, based on the notes taken by Hui-Lan Lu (Bell Labs). The PSTN/Internet Interworking (PINT) WG meeting took place from 19 :30 to 22:00 on Wednesday, December 10. The meeting was chaired by Steve Bellovin (ATT Labs-Research) and Igor Faynberg (Bell Labs/Lucent Technologies). The WG roster registers 155 attendees. Hui-Lan Lu, to whom many thanks, took notes and helped to prepare this report. The proposed agenda of the meeting was as follows: 1. 19:30-19:35 Chairs Agenda bashing 2. 19.35-19:55 L. Conroy Pre-PINT Service Implementation Experiences 3. 19:55-20:10 M. Krishnaswamy Pre-PINT Implementation Report 4. 20:10-20:35 S. Petrack IP Access to PSTN Services: Basic Service Requirements, Definitions, and Architecture 5. 20:35-20:55 H. Schulzrinne SIP for Click-to-Dial-Back and Third-Party Control 6. 20:55-21:10 S. Bellovin On Security Requirements for PINT 7. 21:10-21:30 P. Davidson A Proposal for a Simple Computer Telephony Protocol 8. 21:30-21:45 F. Burg An Architecture and Protocols for Initiation and Control of Telephone Calls From Terminals Connected to a CallBroker over a TCP/IP Connection. 9. 21:45-21:55 Hui-Lan Lu Putting together an Informational RFC 10. 21:55-22:00 Chairs Work items for the next quarter 11. 22:00 All Adjourn During the discussion of item (1) it was proposed and agreed to present item (6) ahead of item (4). In addition, item (8) was moved ahead of item (6), and Tony DeSimone (AT&T) was named its presenter. It was also announced that after the meeting Fred Burg would give a demo supporting the presentation. Item (2) presented the Siemens pre-PINT implementation experiences as proposed for the Informational RFC. Responding to questions, Lawrence Conroy pointed out that the ITU-T CS-1 INAP was used in the prototype and that the protocol with the gateway was service-independent. There was no disagreement with the presented material. Item (3) presented the Lucent pre-PINT implementation experiences, as proposed for the Informational RFC. Murali Krishnaswamy announced that part of his draft summarized the material that had already been presented to PINT, for which reason his presentation was focused on the new aspect: the structure of Management Information Base (MIB), which he had implemented. Responding to questions, Murali explained that the SMS role was to provision the service logic to the service node, and that the Service Data Function (SDF) was implemented as part of the service node. There was no disagreement with the presented material. Item (4) presented the proposed terminology and service requirements (and scenarios) destined for the future standards-track RFC. Scott Petrack clarified, in response to questions, that a) the word "terminal" refers to telephone terminals (not IP hosts) and b) PINT Clients and PINT Servers are IP hosts. There were no disagreements, but two concerns were expressed: 1) The issue of potential overlapping of authorization domains 2) Some services (like conference calling) that rely on the call- control-related features that are outside the present PINT charter. The first issue has been taken off-line; it will be resolved in consultation with the Area Directors. As far as the second issue is concerned, both chairmen re-affirmed that only the charter-related material is relevant to the meeting; the rest of it, although of high quality and interest to others, will be retained in waiting until the present charter has been completed. Item 8 (presented by Tony DeSimone of AT&T) shared a company experience with the implementation of "click-to-dial-back" service. This presentation was unique in that it demonstrated relevant API. This has raised a question of whether AT&T had patents related to the subject. All members of the working group were referred to RFC 2026. Briefly, working groups are free to adopt patent-encumbered technology; however, the patent owners must agree to license the patents on reasonable and non-discriminatory terms. Furthermore, anyone who submits a mechanism that may be protected is obligated to disclose any encumberances he or she is aware of. Finally, anyone and everyone is invited to make the IESG aware of any patents pertaining to any standards-track RFC. In response to other questions, Tony pointed out the interface between the call broker and the switch is a) IP-based, b) reflects the client-server model, and c) in the current implementation, the call broker resides in the telecom server domain (not in the Internet domain). Item 6 presented security requirements for PINT. There were no objections and no questions. Item 5 demonstrated the use of SIP (which is, the protocol of choice for PINT) for supporting click-to-dial-back and other PINT services. In response to a suggestion to have more flexible SDP for passing call-related information, Henning invited contributions on this topic. Item 7 presented SCTP to start a discussion on how this protocol fits within PINT. During the discussion it was noted that the SCTP is a feature-rich CTI protocol that can serve well as the transport mechanism supporting various APIs (e.g., S.100, TSAPI, and JTAPI). A concern was expressed whether the SCTP would be appropriate for the Internet. To address this concern, Paul mentioned that the SCTP, just in order to be useful for the Internet, has been based on the HTTP. The other concern, which still remains open, is how exactly the SCTP can be used to support PINT services efficiently. Item 9 presented the outline of the Informational RFC (no disagreement) and expressed the editor's intention to complete the draft by the end of January. The chairmen thanked the presenters and audience for active, cheerful and cooperative participation, thanks to which an unusually large agenda was covered. The PINT participants were asked to request their time slots for future meetings before the dead-line so that sufficient meeting time be scheduled.