H.225.0V2 comment

Karl Klaghofer karl.klaghofer at MCH.PN.SIEMENS.DE
Wed Sep 24 12:16:28 EDT 1997

Glen, Joerg, Pete, Amotz and others,

In the Sunriver Meeting, the type for the element h4501SupplementaryService in the H323-UU-PDU was changed from "SEQUENCE OF H4501SupplementaryService OPTIONAL" to "OCTET STRING OPTIONAL".

We request to modify the current definition in H.225.0V2 Draft as follows (including a short comment):

"h4501SupplementaryService      SEQUENCE OF OCTET STRING OPTIONAL"
        -- each sequence of octet string is defined as one H4501SupplementaryService APDU
        -- as defined in TABLE3/H.450.1

Reason for change:
With the previous definition (SEQUENCE OF H450SupplementaryService) it was possible to signal multiple H450SupplementaryService APDUs within one User-user information element.
This is required if APDUs which require different NetworkFacilityExtension and/or EntityType encoding have to be sent within one single message.
With just using "OCTET STRING", we see compatibility problems between different vendors Supplementary Service implementations in case of multiple H4501SupplementaryService APDUs beeing used.
Remark: The alternative - to change the H.4501SupplementaryService APDU structure - should be avoided at this stage.

The comment "-- each sequence ....." as proposed above shall give at least textual linkage between H.225.0V2 and the corresponding H.450.1 module.

Karl Klaghofer
Siemens AG Munich
Hofmannstr. 51, D-81359 Munich, Germany
Tel.:   +49 89 722 31488
Fax.:   +49 89 722 23977
email:  karl.klaghofer at mch.pn.siemens.de

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