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Versions: 00                                                            
Media Gateway Control                                      Sarah Cornel
                                                       C. Michael Brown
Internet Draft                                          Nortel Networks
Document: draft-cornel-megaco-enhancedd-00.txt                July 2000
Category: Informational


Enhanced DTMF Detection Package for Megaco/H.248

   Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026 [1].


   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups. Note that
   other groups may also distribute working documents as Internet-
   Drafts. Internet-Drafts are draft documents valid for a maximum of
   six months and may be updated, replaced, or obsoleted by other
   documents at any time. It is inappropriate to use Internet- Drafts
   as reference material or to cite them other than as "work in
   progress."
   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt
   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.



1. Abstract

   This document provides proposed definitions for a supplemental
   package for Megaco/H.248. This package addresses enhanced support of
   DTMF detection.


2. Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in
   this document are to be interpreted as described in RFC-2119 [2].


3. Enhanced DTMF Detection Package Definition

3.1 Enhanced DTMF Detection Package
   PackageID: edd
   Version: 1
   Extends: dd version 1

   This packages extends the mechanisms for detecting and reporting
   DTMF tones. Additionally, it changes the way the digit maps are
   interpreted.

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                 draft-cornel-megaco-enhancedd-00.txt        July 2000


   The package depends on tones described in packages dg and dd (basic
   DTMF generator package and DTMF detection package).

   Properties
   None.

   Events
   DigitMap Matched Completion Event
   EventID: mce
   EventsDescriptor parameters:

   Digit map processing is activated only if a digit map parameter is
   present, specifying a digit map by name or by value. Other
   parameters such as a KeepActive flag, embedded Events or Signals
   Descriptors may be present.

   ObservedEventsDescriptor parameters:
        DigitString
        ParameterID: ds (0x0001)
        Type: string of digit map symbols (possibly empty) returned as
   a quotedString.
        Possible values: a sequence of the characters "0" through "9",
   "A" through "F", and the long duration modifier "Z".
        Description: the portion of the current dial string as
   described in the procedures section which matched all of an
   alternative event sequence specified in the digit map.
        Termination Method
        ParameterID:    Meth (0x0003)
        Type: enumeration
        Possible values:
                "UM" (0x0001) Unambiguous match
                "FM"  (0x0003) Full match, completion by timer expiry
   or unmatched event
        Description: indicates the reason for generation of the event.
   See the procedures section.


   Signals
   None.

   Statistics
   None.

   Procedures

   Procedures for detecting this event are different than those for the
   completion event (dd/ce). Procedures for invoking these procedures
   apply if the matched completion event is requested. It should be
   noted that the completion event (dd/ce) and the matched completion
   event (edd/mce) are incompatible. A request for both these events
   should treat the completion event (dd/ce) as the event with
   precedence.


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                 draft-cornel-megaco-enhancedd-00.txt        July 2000

   The following describes the procedures for the matched digit map
   completion event.A digit map is active while the events descriptor
   which invoked it is active and it has not completed. A digit map
   completes when:

   an alternative event sequence has been matched and no other
   alternative event sequence in the digit map could be matched through
   detection of an additional event (unambiguous match), or

   an event has been detected (usually another digit or timer expiry)
   such that a match to a complete alternative event sequence of the
   digit map will be impossible no matter what additional events are
   received, and at least one event sequence is matched (full match).

   Upon completion, a digit map completion event as defined in this
   package providing the events being mapped into the digit map shall
   be generated. At that point the digit map is deactivated, however
   collection of events into the _event buffer_ continues until
   explicitly stopped.

   Alternatively, one of the following conditions may be detected:

   an event has been detected such that a match to a complete
   alternative event sequence of the digit map will be impossible no
   matter what additional events are received, and no event sequence is
   matched, or

   a timer has expired and no sequence is matched.

   If these conditions occur, the contents of the current dial string
   should have the first event in its buffer flushed, and the current
   digit map should be reapplied. These are considered to be  reset
   conditions for the digit map. This process continues until either
   there is a match, or the request is terminated.

   Additionally, unless noted here, the processing of the current dial
   string and the digit map proceeds like the processing of a
   completion event (dd/ce) .


4. Formal Syntax

   Not Applicable

   The following syntax specification uses the augmented Backus-Naur
   Form (BNF) as described in RFC-2234 [3].


5. Security Considerations

   Not Applicable

6. References


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                 draft-cornel-megaco-enhancedd-00.txt        July 2000


   1  Bradner, S., "The Internet Standards Process -- Revision 3", BCP
      9, RFC 2026, October 1996.

   2  Bradner, S., "Key words for use in RFCs to Indicate Requirement
      Levels", BCP 14, RFC 2119, March 1997

   3  Crocker, D. and Overell, P.(Editors), "Augmented BNF for Syntax
      Specifications: ABNF", RFC 2234, Internet Mail Consortium and
      Demon Internet Ltd., November 1997



7. Acknowledgments



8. Author's Addresses

   Sarah Cornel
   Nortel Networks
   4008 Chapel Hill Road
   Research Triangle Park, NC USA 27709
   Phone: (919) 991-2853
   Email: sarahc@nortelnetworks.com

   C. Michael Brown
   Nortel Networks
   4008 Chapel Hill Road
   Research Triangle Park, NC USA 27709
   Phone: (919) 991-7767
   Email: C.Michael.Brown@nortelnetworks.com

9. Full Copyright Statement

   "Copyright (C) The Internet Society (date). All Rights Reserved.
   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph
   are included on all such copies and derivative works. However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.  The limited permissions granted above are perpetual and
   will not be revoked by the Internet Society or its successors or
   assigns.  This document and the information contained herein is
   provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE
   INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF

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                 draft-cornel-megaco-enhancedd-00.txt        July 2000

   THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE."

10. Expiration Date

   This memo is filed as draft-cornel-megaco-enhancedd-00.txt, and
   expires January 2001.
















































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