User Information or Information in H.225.0

Glen Freundlich ggf at
Thu Feb 19 11:09:27 EST 1998

In H.225.0 V1, section 7.3.6 describes the User Information message. The
related ASN.1 definition is named UI-UUIE, but the table and caption
(Table 9) describe the Q.931 Information message.

H.323 V2 describes the use of the Information message (for example, to
support overlap sending), but H.225.0 V2 contains no section describing
the Information message and no ASN.1 has been defined specifically for
use with the Information message.

Possible fixes seem to be:

1 - rename section 7.3.6 from "User Information" to "Information" and
add some text stating that the Information message is used to support
overlap sending

2 - correct section 7.3.6 to align with the User Information message
(correct the table, correct the reference to Q.931) and add a new
section (and associated ASN.1) for the Information message

3 - other suggestions?

As backward compatibility is a concern, the best approach depends on
existing implementations and the use of User Information or Information
messages. So, a vendor that decides to implement might interpret this to
be a User Information message with a different set of information
elements (not as described in table 9/H225) or an Information message
with the set of information elements as defined in table 9.

Please comment.

Glen Freundlich (editor H.225.0)

Glen Freundlich                           ggf at
Lucent Technologies                       office: +1 303 538 2899
11900 N. Pecos                            fax: +1 303 538 3907
Westminster, Colorado 80234  USA

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