User Information or Information in H.225.0
pete.cordell at BT-SYS.BT.CO.UK
Fri Feb 20 08:43:58 EST 1998
On closer examination there seem to be a few errors in Table 4/H.225.0.
The 6th paragraph of section 7.1/H.225.0 (white paper at least) says
that the "The procedures of Q.931/Section 3.1 for circuit mode
connection setup are followed." According to this section the messages
"User Information" and "Congestion Control" do not apply. They are used
in the call-independent signalling part that we are not using.
Also "Status Inquiry" is spelt "Status Enquiry" in Q.931 (not that I
would know what is the right form!!!).
We need to go with option 1 of your suggestions. The Information
message is what we need for overlap sending. The description part of
7.3.6 is correct for the "Information" message (including the reference
to the table in Q.931).
If we can silently remove "Congestion Control" at the same time so much
E-Mail: pete.cordell at bt-sys.bt.co.uk
Tel: +44 1473 646436
Fax: +44 1473 645499
>From: Glen Freundlich[SMTP:ggf at LUCENT.COM]
>Sent: 19 February 1998 16:09
>To: ITU-SG16 at MAILBAG.INTEL.COM
>Subject: User Information or Information in H.225.0
>In H.225.0 V1, section 7.3.6 describes the User Information message.
>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
>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
>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.
>Glen Freundlich (editor H.225.0)
>Glen Freundlich ggf at lucent.com
>Lucent Technologies office: +1 303 538 2899
>11900 N. Pecos fax: +1 303 538 3907
>Westminster, Colorado 80234 USA
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