Megaco Errata
RFC 2886

Document Type RFC - Historic (August 2000; No errata)
Obsoleted by RFC 3015
Last updated 2013-03-02
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Network Working Group                                          T. Taylor
Request for Comments: 2886                               Nortel Networks
Category: Standards Track                                    August 2000

                             Megaco Errata

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

1. Abstract

   This document records the errors found in the Megaco/H.248 protocol
   document [2], along with the changes proposed in the text of that
   document to resolve them.

2. Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC-2119 [1].

3. Errata

   All section numbers are those of the relevant text of [2].

   Section: 2 "References"
   Editorial: Add missing references to I.363.5 (AAL5) and RFC 1661

   Editorial: delete unused reference to Q.724.

   Editorial: Leave Recommendations referred to in Annex C undated,
   implying latest issue.

   Editorial: add reference to RFC 2805, the Megaco requirements

Taylor                      Standards Track                     [Page 1]
RFC 2886                     Megaco Errata                   August 2000

   Section: 4 "Abbreviations"
   Editorial: delete unused abbreviation BRI.

   Editorial: add explanations for GSM and IVR.

   Section: 6.2.2 "TerminationIDs"
   Issue: Not clear what wildcard union responses look like.

   Resolution: Add the following text:
    "ie. Given termination Ta with properties p1=a, p2=b, and
   termination Tb with properties p2=c, p3=d a UNION
   response would be T* p1=a, p2=b,c, p3=d."

   Section: 6.2.4 "Termination Properties and descriptors"
   Issue: Says that property values set in Null context are remembered
   and reinstated when termination returns to Null.  Contradicts latest
   text in 7.2.3.

   Resolution: Rewrite the first paragraph from the third sentence
   onward, to read:  "Most properties have default values, which are
   explicitly defined in this standard  or in a package (see Section 12)
   or set by provisioning.  If not provisioned otherwise, all
   descriptors except for TerminationState and LocalControl default to
   empty/"no value" when a termination is first created or is returned
   to the null context.  The default contents of the two exceptions are
   described in sections 7.1.5 and 7.1.7."

   Issue: DigitMap entry in table makes explicit reference to DTMF
   tones, but is also intended to apply to other in-band signalling

   Resolution: Change existing text to new one as follows: "Defines
   patterns against which sequences of a specified set of events are to
   be matched so they can be reported as a group rather than singly."

   Section: 6.2.5 "Root Termination"
   Issue: Root can have statistics as well as properties and events.

   Resolution: add "statistics" to the fourth sentence of the first
   paragraph, listing what is valid for Root.  Add "statistics" to what
   AuditValue can return for Root.

Taylor                      Standards Track                     [Page 2]
RFC 2886                     Megaco Errata                   August 2000

   Section: 7.1 "Descriptors"
   Issue: it is unclear how to express empty descriptors in responses to
   the MGC.

   Proposed resolution: In section 7.1, add the following text after the
   sentence: "Descriptors may be returned as output from a command.":
   "In any such return of descriptor contents, an empty descriptor is
   represented by its name unaccompanied by any list."

   In the ASN.1, add the following choice to the AuditReturnParameter

     "emptyDescriptors               AuditDescriptor,"

   In the ABNF, add the choice auditItem to the production

   Section: 7.1.1 "Specifying Parameters"
   Issue: Third paragraph (discussing unspecified parameters): not clear
   which parameters are mandatory.

   Resolution: Replace the first two sentences (each beginning with the
   word "unspecified") with the following text:  "If a required
   descriptor other than the Audit descriptor is unspecified (i.e.
   entirely absent) from a command, the previous values set in that
   descriptor for that termination, if any, are retained.  A missing
   Audit descriptor is equivalent to an empty Audit descriptor.  The
   behaviour of the MG with respect to unspecified parameters within a
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