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RFC 1789

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INETPhone: Telephone Services and Servers on Internet


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Network Working Group                                            C. Yang
Request for Comments: 1789                     University of North Texas
Category: Informational                                       April 1995

         INETPhone: Telephone Services and Servers on Internet

Status 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.


   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).


   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

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 indispensable

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   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

   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 full

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   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
   (see Section 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

     (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;

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     (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 (see
         Section 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 (see Section 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.

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5. 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

   An outline of the proposed open-partnership scheme is listed as

     (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

     (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.

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8. 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,

   [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