Update draft of H.bmultipoint

Hidenobu Harasaki harasaki at CCM.CL.NEC.CO.JP
Tue Dec 9 08:49:05 EST 1997

Dear Ms. Li Yan, Mr. Sakae Okubo and other Q.12/16 experts,

Thank you for your contribution for H.bmultipoint.

Updated draft of H.bmultipoint (Version 1.1) is now available on
ftp.gctech.co.jp incoming directory.

Filename is "hbmult-v11.doc".
The cover page of the file is attached below.

I greatly count on expert's contribution to finalize the draft.

Best regards,


Hidenobu Harasaki           harasaki at ccm.CL.nec.co.jp
Principal Researcher        C&C Media Research Labs., NEC Corporation
                            Phone: +81 44 856 8083    Fax: +81 44 856 2232

This draft is H.bmultipoint version 1.1, which is an updated version of
Version 1 presented at Sunriver meeting.

During Sunriver meeting,  the following comments or suggestions were raised.

1. Delete "using H.246 gateways" from the second sentence and to
   describe in Section 9 a couple of possibilities; use of H.246 functions,
   use of interopration mode, transcoding, etc.  It was also suggested to
   focus on H.320 as a typical case of other H-series terminals.

2. Dynamic VC change (i.e. between a multicast leaf and a point-to-point
   party when the current speaker switches) may be expensive and suffer
   noticeable delay. Since VC setup is not designed to guarantee to work in
   a real-time fashion. it needs some time (It could be 1.5 -20 seconds was

3. Include system configuration of H.bmultipoint MCU as in H.231.

4. Include reference to service Recommendations such as F.700, F.710,

5. Concentrate on multicast by MCU and multicast by the root MCU
   initiated join.

6. Editor can use existing texts in H.140, H.231/H.243 and other related
   exiting Recommendations.

7. Tables 1 and 2 for master-slave determination need correction.

8. The next draft of H.bmultipoint will include the following
   implementation alternatives as information: remultiplexing, transcoding,
   use of layered coding, and  use of H.320/H.321 interoperation mode.

The editor needs expert's assistances to reflect some of the above
comments or suggestions, and to fill the blanks in the draft Recommendatation.

* Specific text referring to F.700, F.710 and F.720, and where the text
  should be inserted.

* Is there any solution to cope with the problem No. 2 above?

* In Section 6,  call setup/release scenario is exactly the same as
  H.310 except point-to-multipoint audiovisual connection setup procedure.
  How a terminal can join a conference as a multicast leaf using H.245
  negotiation?  If the terminal is ROT, the MCU can automatically invite
  it as a multicast leaf.  But considering the case of  RAST, do we need
  to add H.245 message? Or, the terminal shall be declare that I'm a ROT?

* Chapter 5 shall be a general system description, while chapter 7
  explicitly specifies how the MCU behave.   What are the essential
  specifications in Chapter 7?

Any contributions toward the determination in January 1998 are solicited.

Hidenobu Harasaki (harasaki at ccm.cl.nec.co.jp),  editor for H.bmultipoint

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