Movatterモバイル変換

Network Working Group                                            C. YangRequest for Comments: 1789                     University of North TexasCategory: Informational                                       April 1995INETPhone: Telephone Services and Servers on InternetStatus of this Memo   This memo provides information for the Internet community.  It does   not specify an Internet standard of any kind.  Distribution of this   memo is unlimited.IESG Note   Internet Engineering Steering Group comment from the Transport Area   Director: Please note well that this memo is an individual product of   the author.  Work on standards and technology related to this topic   is additionally taking place in the IETF in the Multiparty MUltimedia   SessIon Control Working Group (MMUSIC).Abstract   INETPhone is a true telephone service through the Internet. It   integrates the local telephone networks and the Internet using   INETPhone servers. Thus a long distance call can be split into two   local calls and an Internet connection, which is transparent to end   users. Such a phone service through Internet will be a major step   towards integrated services on Internet. In order to support the   INETPhone and lay down the ground rules of the service, a scheme of   "open partnership" is proposed, so that the entire Internet community   can have the equal opportunity and benefits from the INETPhone   service.1. Introduction   The success of traditional Internet services, such as the electronic   mail, the file transfer, and the remote machine access, has inspired   a row of new network applications -- the world-wide information web,   voice and video conferencing, and network telemarketing are just a   few to mention.  With the further development in infrastructure and   the architecture of integrated, multimedia information services   [1,2,3], certainly the Internet will play a crucial role in shaping   up the future of so-called information super-highway.   Among many new applications, the voice communication through Internet   bears perhaps the most potential impact, since it competes directly   with the telephone communication, which has become an indispensableYang                                                            [Page 1]

RFC 1789       Telephone Service and Servers on Internet      April 1995   part of the modern society.  Recently, many software packages are   available, either commercially or as public free-ware, which supports   voice communication on Internet.  Some of these products are targeted   directly as possible substitution for long distance telephone   services.  However, so far, all such products only support voice   communications using a computer that is on the Internet or is   connected, via a SLIP link, to the Internet [4].   This RFC presents a true telephone service, called INETPhone, which   supports voice communication through the Internet.  INETPhone   integrates the local phone network with the Internet. The phone   network provides local access of INETPhone service with the existing   telephone facilities, whereas the Internet delivers the packets of   voice communication over long distances.  The service of INETPhone is   illustrated by the following scenario.  Assuming a user at area A   wants to call another user in area B. The user first makes a local   call to an INETPhone server in area A. After the connection, the user   keys in the remote phone number in area B to the server. Then the   server in area A makes a connection to another INETPhone server in   area B, and requests the remote server to dial, as a local call, the   phone number in area B. Therefore, a long distance phone connection   between users in area A and B is established via two local phone   connections and one Internet connection between two INETPhone   servers.   The INETPhone provides a general service of voice communication on   Internet compatible to the existing telephone service.  The   motivation in developing and experimenting the INETPhone service can   be two-folds: on the one hand, a general telephone service on the   Internet will be a major step towards integrated services on Internet   and a great challenge to the future development of Internet   infrastructure and protocol architecture; on the other hand, the   entire Internet community can take the advantage from the cheap and   convenient voice communication of the INETPhone service.2. Design Philosophy   The design philosophy of the INETPhone differs from the most of   current voice communication services on Internet in three basic   aspects: integrating the existing telephone networks with the   Internet; using the INETPhone servers to carry out the task of voice   packet delivery on Internet; and an open-partnership of establishing   the INETPhone service on Internet.  The discussion of each of these   aspects is given as follows.   The conventional telephone service is the most popular and convenient   means for voice communication across distances. Any serious effort to   integrate voice communication on the Internet should take the fullYang                                                            [Page 2]

RFC 1789       Telephone Service and Servers on Internet      April 1995   advantage of this well-established service.  The INETPhone bridges   the existing telephone network with the Internet, so that the access   of the INETPhone service will be totally based on the local phone   services and facilities. This will lead to a much easier access and   broader user population than the approaches of computer-based access.   The INETPhone service is based on the client-server model, in which a   group of INETPhone servers are responsible for accepting/initiating   local calls and deliverying voice packets across the Internet.  The   general users (as clients) can easily access the service through a   conventional phone with a local call. The creation of such INETPhone   servers eases the burden from general users, and provides services of   voice communication on the Internet in a more efficient and   manageable manner.   Hundreds even thousands of INETPhone servers will be required for the   wide coverage of INETPhone services on the Internet (to cover all   areas within US, at least one server needs to be installed in each   area of phone area code).  Instead of letting few industrials   monopolize such a service on the Internet, an alternative approach   based on an open-partnership scheme of INETPhone service is proposed   (seeSection 5), which will give equal opportunity and benefits to   the entire Internet community.3. INETPhone Servers   The central components of the INETPhone service are its servers on   Internet.  The server acts as a gateway between the telephone network   and the Internet.  For this purpose, the server will have both   interfaces to a computer network and the telephone network.   Currently, there are many commercial telephone interface cards   available on the market (such as Dialogic's Voice Boards [5]), which   support various telephone operations of detecting/generating   telephone signals (ring, DTMF, etc. [6]), receiving/initiating phone   calls, recording (digitizing and compressing) or playing back audio   signals, and monitoring the progress of a phone call.   With the support of necessary hardware interfaces, the function of an   INETPhone server includes:     (a) Receive a local call or accept a connection from a remote         server;     (b) Identify the PIN of a local call and determine if to proceed         the call or not;     (c) Accept a phone number for remote dialing from a local call;Yang                                                            [Page 3]

RFC 1789       Telephone Service and Servers on Internet      April 1995     (d) Look up the local directory for a remote server of a         requested call;     (e) Make a connection to a remote server;     (f) Make a local phone call upon the request of a remote server;     (g) Maintain full-duplex, real-time exchanges of voice packets         via Internet;     (h) Maintain information exchanges with Directory Servers (seeSection 4);     (i) Handle exceptional conditions, such as long delay or drop of         voice packets;     (j) Monitor quality of service and keep accounting information.   The above listed functions represent probably the minimal   requirements for each INETPhone server. Some further important   features, such as compression/decompression, security, multicasting,   and voice mail need also to be considered when a real service of   INETPhone is launched on the Internet.  Since a general public of the   Internet community might be involved in this proposed INETPhone   service, it is probably necessary to set an open standard in the   building of INETPhone servers (seeSection 5).4. Directory Servers   The main philosophy behind the INETPhone service is to reduce a long   distance phone call into two local calls and an Internet connection.   Therefore, an INETPhone server will always be identified by its IP   address with its local area code of the phone number (also possibly   with its sub-regional number).  In order to support a dynamic   configuration of INETPhone servers on the Internet, a Directory   Server(s) (DS) will be required to map between IP address and area   code of INETPhone servers, which in some sense, is similar to the   functions of a Name Server (such as the BIND [7]).  After an   INETPhone server is installed on the Internet, it needs to register   itself with a DS.  The mapping information at DS will be disseminated   to INETPhone servers for the search of a remote server in response to   a requested phone call.  Local cache of mapping information may also   be maintained at INETPhone servers to alleviate communications   between INETPhone servers and Directory Server(s).  Again, the   function of a Directory Server for the INETPhone may require another   open specification.Yang                                                            [Page 4]

RFC 1789       Telephone Service and Servers on Internet      April 19955. Open Partnership   Voice communication and telephone service are important parts for   providing integrated information services over the Internet.  With   the current trends of commercialized services over the Internet,   sooner or later, some kind of telephone services will be launched on   the Internet by some private companies.  On the other hand, the   operation of the INETPhone service will depend on the installment of   enough INETPhone servers over the Internet, which can be achieved   through a cooperative effort of the entire Internet community.  This   RFC proposes an open-partnership scheme for the INETPhone service,   which provides equal opportunity and benefits to the entire Internet   community.   An outline of the proposed open-partnership scheme is listed as   follows:     (a) Any organization or individual person can join or withdraw         from this open-partnership on a voluntary base.     (b) In order to join the partnership (therefore becoming a member         of the partnership), an organization or a person should at         least install and maintain an INETPhone server on the         Internet with the equal capacity of lines for call-in and         dial-out services.     (c) Each member of the partnership has the equal right to use the         INETPhone service through any INETPhone servers on the         Internet.  All services will bear the same charges based on         the number of bytes transmitted through the Internet and         whatever the rate (if any) laid down by the Internet         authority.     (d) A not-for-profit consortium will be formed from the         representatives of all members of the partnership. The main         task of the consortium is to establish all regulations and         specifications of the INETPhone service, and to coordinate         the execution of these rules by all the members.7. Recommendation   If there is enough interests in the INETPhone service from the   Internet community, the IAB may need to consider forming a special   task force or working group to further look into the matter.Yang                                                            [Page 5]

RFC 1789       Telephone Service and Servers on Internet      April 19958. References   [1] Adie, C., "Network Access to Multimedia Information",RFC 1614,       Edinburgh University, May 1994.   [2] Braden, R., Clark, D., and S. Shenker, "Integrated Services in       the Internet Architecture: an Overview",RFC 1633, ISI, MIT,       Xerox PARC, June 1994.   [3] Weider, C., and P. Deutsch, "A Vision of an Integrated Internet       Information Service",RFC 1727, Bunyip Information Systems,       December 1994.   [4] Walters, R., "Computer Telephone Integration", Artech House       Publishers, Norwood, MA, 1994.   [5] Dialogic Corporation, "Voice Hardware Reference", Parsippany, NJ,       1994.   [6] Noll, M., "Introduction to Telephones and Telephone Systems", 2nd       Ed., Artech House Publishers, Norwood, MA, 1991.   [7] Albitz, P., and C. Liu, "DNS and BIND", O'Reilly & Associates,       Sebastopol, Calif., 1992.8. Security Considerations   Security will be an important issue in the INETPhone service.  As a   general proposal, however, this RFC chooses to leave this topic for   future discussions.9. Acknowledgement   This RFC is based on a currently undergoing project supported by the   Department of Computer Science, University of North Texas.10. Author's Address   Cui-Qing Yang   Dept. of Computer Science   University of North Texas   P.O. Box 13886   Denton, TX 76203   Phone: (817) 565-2822   Fax: (817) 565-2799   EMail: cqyang@cs.unt.eduYang                                                            [Page 6]