ASN problem in H.245v11

mike.nilsson at BT.COM mike.nilsson at BT.COM
Wed Jul 13 04:24:21 EDT 2005


I do not think this is an error or a problem in any sense as the bits
that are transmitted are not changed.

The reason for the change is as follows.

Up to and including version 10, I, as editor of H.245, have maintained
my own version of the recommendation, and as each version has been
approved, I have submitted it to the ITU-T TSB for publication. They
then made editorial changes to it to align the look and feel of it to
the ITU-T template. Each time I gave them a new version, they would have
to make similar changes.

Due to the rapid approval of new versions, 10 versions in 10 years, the
ITU-T publication process was continually a little behind. But by
version 11 they had caught up, and the decision was made for future
(including version 11) editor's drafts to be based on the previous ITU-T
published version.

Hence various changes to spelling and style have been made between the
editor's drafts of version 10 and 11 - you have found one of them.
Hopefully none of the differences are significant - a lot of effort went
into verifying this.

Anyone looking at the published versions would not have seen any such
changes between versions 10 and 11 - they would only see the intended
technical enhancements.

I hope this clarifies the situation.

Best regards

Mike Nilsson

Mike Nilsson 
Multimedia Analysis and Coding 

Sirius House (B54-MH), Room 124 
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-----Original Message-----
From: Giles Chamberlin [mailto:giles.chamberlin at] 
Sent: 11 July 2005 15:52
To: itu-sg16 at
Subject: ASN problem in H.245v11 

Latest H.245v11 document (H245WCM28.doc) obtained from

has an error in the asn.1 definition:


GenericMessage                                             ::=SEQUENCE


      messageIdentifier               CapabilityIdentifier,

      subMessageIdentifier            INTEGER(0..127)  OPTIONAL,


      messageContent                  SEQUENCE OF GenericParameter




subMessageIdentifier appears to have been spellchecked and is now
different to previous versions. (It was subMessageIdentifer in v10).

Giles Chamberlin
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