Dear Sunil Chandra,

For question 2,3, I don't have any idea. And for other questions, my opnion follows,

Sunil Chandra wrote:

Hi Chris,

  I have following queries related to MC and MCU.

  1. In H.323 section 6.2.8.4, there is a table which gives the terminal
  types values for various terminal types. In this table there are certain
  entries marked as NA. Does this mean that these terminal types are not
  possible? for example, an MCU is not possible without an MC.

I think some component which do not have MC is never be an MCU.

  4. Is it always necessary to have an MC in Gatekeeper?

A Gatekeeper which do not have MC is not concerned with master-slave determination. So, in this table, a Gatekeeper which do not have MC was not considered.

  5. If a call signalling is routed through Gatekeeper, and there exists an
  MCU which is not involved in this call. Is it possible for the Gatekeeper
  to involve this MCU to create an ad-hoc conference from this call. If yes,
  what is the procedure? If not, why?

I think, H.323 terminal can involve other MCU's MC to make ad-hoc multipoint conference. And signalings between them is outside of standard. For example, someone can make MC as a stand-alone program like UNIX daemon, and use it for other terminal's ad-hoc conference expansion.

Best wishes,

soo.