Development of Decomposed Gateway Architecture

[Tom-PT Taylor]

This note is to point out the follow-up work required in the light of the
Monterey meeting's adoption of the revised Gateway functional architecture
as shown in TD-34 (Monterey).  I am prepared to contribute to that work.
People may wish to comment on the priorities of definition of the different
interfaces.

First point: I followed up Bob Callaghan's pointers to the layer 4
interfaces applicable to our J:c interface (per the TD-34 definition).  The
relevant references are the SDL charts shown in Annex A of Q.931 and Annex H
of Q.764 respectively.  These show  the messages exchanged over the J:c
interface for their respective protocols, but do not show their content.  So
that's one work item.

Second point: Annex A of Q.931 shows messages going between a Q.931 Protocol
Control block and two higher blocks: Call Control and Resource Control
respectively.  Annex H of Q.764 is more complicated: it shows Call Control
above the ISUP User Part, but three blocks within it: Signalling Procedure
Control, Call Processing Control, and Circuit Supervision Control.  I think
we should have a Call Control block in our picture, at the same level as our
High-Layer Resource Control.  I also think the ISUP Circuit Supervision
Control should report into High-Layer Resource Control rather than Call
Control.

Third point: the messaging on our ?:b interface can probably be derived from
the Q.931 SDL.  The content also has to be worked out.  Another couple of
work items.

Final point: how to determine the content of the ?:e (abstracted H.245)
interface and where it should flow?  Definitely some detailed work items
here.



Tom Taylor
E-mail: taylor at nortelnetworks.com  (internally Tom-PT Taylor)
Tel.: +1 613 765 4167     (internally 395-4167)
FAX: +1 613 763 7236     (internally 393-7236)