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].
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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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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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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
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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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