One document matched: draft-ietf-pppext-callback-ds-00.txt

Network Working Group                                 W. Simpson, Editor
Internet Draft                                                DayDreamer
expires in six months                                      November 1996


                              PPP CallBack
                  draft-ietf-pppext-callback-ds-00.txt


Status of this Memo

   Distribution of this memo is unlimited.

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Abstract

   The Point-to-Point Protocol (PPP) [1] provides a standard method for
   transporting multi-protocol datagrams over point-to-point links.  PPP
   defines an extensible Link Control Protocol (LCP) for establishing,
   configuring, and testing the data-link connection.  This document
   defines several additional LCP features that have been suggested over
   the past few years.








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1.  Additional LCP Configuration Options

   The Configuration Option format and basic options are already defined
   for LCP [1].

   Up-to-date values of the LCP Option Type field are specified in the
   most recent "Assigned Numbers" [2].  This document concerns the fol-
   lowing values:

      13      CallBack



1.1.  CallBack

   Description

      This Configuration Option provides a method for an implementation
      to request a dial-up peer to call back.  This option might be used
      for many diverse purposes, such as savings on toll charges.

      When CallBack is successfully negotiated, and authentication is
      complete, the Authentication phase proceeds directly to the Termi-
      nation phase, and the link is disconnected.

      Then, the peer re-establishes the link, without negotiating Call-
      Back.

      Implementation Notes:

         A peer which agrees to this option SHOULD request the Authenti-
         cation-Protocol Configuration Option.  The user information
         learned during authentication can be used to determine the user
         location, or to limit a user to certain locations, or merely to
         determine whom to bill for the service.

         Authentication SHOULD be requested in turn by the implementa-
         tion when it is called back, if mutual authentication is
         desired.

   A summary of the CallBack Option format is shown below.  The fields
   are transmitted from left to right.









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    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |   Operation   |  Message ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      13

   Length

      >= 3

   Operation

      The Operation field is one octet and indicates the contents of the
      Message field.

      0       location is determined by user authentication

      1       Dialing string, the format and contents of which assumes
              configuration knowledge of the specific device which is
              making the callback.

      2       Location identifier, which may or may not be human read-
              able, to be used together with the authentication informa-
              tion for a database lookup to determine the callback loca-
              tion.

      3       E.164 number.

      4       Distinguished name.

   Message

      The Message field is zero or more octets, and its general contents
      are determined by the Operation field.  The actual format of the
      information is site or application specific, and a robust imple-
      mentation SHOULD support the field as undistinguished octets.  The
      size is determined from the Length field.

      It is intended that only an authorized user will have correct site
      specific information to make use of the CallBack.  The codifica-
      tion of the range of allowed usage of this field is outside the
      scope of this specification.





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Security Considerations

   Security issues are briefly discussed in sections concerning the
   CallBack Configuration Option.


Acknowledgements

   Special thanks to Morning Star Technologies for providing computing
   resources and network access support for writing this specification.


References

   [1]   Simpson, W., Editor, "The Point-to-Point Protocol (PPP)",
         RFC-1661, December 1993.

   [2]   Reynolds, J.K., Postel, J.B., "Assigned Numbers", RFC-1700,
         July 1992.

   [3]   Simpson, W., Editor, "PPP in HDLC-like Framing", RFC-1662,
         December 1993.





























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Contacts

   Comments about this document should be discussed on the ietf-
   ppp@merit.edu mailing list.

   This document is a submission to the Point-to-Point Protocol Working
   Group of the Internet Engineering Task Force (IETF).  The working
   group can be contacted via the current chair:

      Karl Fox
      Ascend Communications
      3518 Riverside Drive  Suite 101
      Columbus, Ohio  43221

          karl@MorningStar.com
          karl@Ascend.com

   Questions about this document can also be directed to:

      William Allen Simpson
      DayDreamer
      Computer Systems Consulting Services
      1384 Fontaine
      Madison Heights, Michigan  48071

          wsimpson@UMich.edu
          wsimpson@GreenDragon.com (preferred)
          bsimpson@MorningStar.com























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