Subject: [Megaco] Points for clarification on H.248.16 extended DTMF Detection Package.

From: "Dal Chohan" <[email-masked]>
Date: Wed, 14 Jan 2004 14:01:23 -0000

Whilst studying the H.248.16 "xdd" package I noticed the following anomalies/points for clarification:

1. Unmatched event parameter ("extra") 

(a) According to H.248.1 version 2 "clause 7.1.14.5 item 5 (a)" this suggests that the reporting off the unmatched event is controlled by the digit map completion event. But this capability doesn't appear to be included in the "xdd" package. Is the assumption that the "umatched event" parameter is always reported when completion is triggered by an event that results in no remaining candidates ?

(b) The current text associated with the "extra" parameter under the heading "possible values" suffers from too many "nots" and is potentially confusing to the reader - 'Not included if completion was not triggered by an unmatched event (extra digit)'. This sentence should be deleted, because the text under the heading "description" adequately describes the case when this parameter is included.

2. Shortest Digit Match

Item 5 of the procedures in H.248.16 for package "xdd" indicates that in the case where  no candidates remain for match, then a digit completion event is sent with a"partial match". However, no procedures are defined with respect to how the additional event that resulted in 'no candidates' for match is handled as per H.248.1 version 2 clauses 5(a) and 5 (b). Is the extra digit discarded (if specified by parameter "xdd") or buffered and is the event reported via parameter "extra" etc.

Dal Chohan