[MEDIACTRL] Control Framework SDP Review - Issue 4

[Chris Boulton <chris at ns-technologies.com>]

Issue 4:

I also note that as far as I can tell, neither SDP nor the CFW SYNC
message provides any indication of whether a given endpoint thinks it's
a Control Client or a Control Server.  It seems this is supposed to be
implicit based on the directionality of the initial SIP INVITE request
that set up the call, but in some cases this can get confused in SIP
(notably given third-party call control), and I'm sure the results could
be odd, and hard to diagnose, if two clients or two servers accidentally
end up connected.  Perhaps this should be a property of the relevant
control package, rather than of CFW proper, but it seems like it should
be addressed.

[Chris] The 'roles' of the client and server are logical within the the Media Control Channel Framework and is not tied to the directionality of the SIP INVITE.  It is really up to the Control package to specify 'if' and 'when' messages can be sent (in the template).  The draft states:

'Consider the following simple example for session establishment
  between a Client and a Server (Note: Some lines in the examples are
  removed for clarity and brevity).  Note that the roles discussed are
  logical and can change during a session, if the Control Package
  allows.'

I will expand on this text and make it clearer to the reader that the roles are logical.  Is that acceptable?

--
Chris Boulton
CTO & Co-founder
NS-Technologies <http://www.ns-technologies.com>
m: +44.7876.476681