[comp.protocols.iso] Session requirements negotiation

Isaac@gui.consumers.com (12/04/90)

Dear OSI gurus,

According to X.215, section 12.1.2.7,

  "... additional SS-user session requirements which were not included in the 
  indication, may be included in the response.  SS-user session requirements 
  that are proposed in both the indication and the response are the ones 
  selected for use on the session connection."

This section has been bugging me for years.  Can anyone tell me the advantage 
of allowing the responding SS-user to propose additional SS-user session 
requirements that it knows already that these will not be selected for use 
anyway?

Thanks in advance for any enlightening thoughts.  Puzzled,

Isaac Chan, Consumers Software Inc. <Isaac@gui.consumers.com>

mckenzie@bbn.com (Alex McKenzie) (12/18/90)

I'm not positive, but I would guess that this is a "backward
compatibility" feature introduced when the current Session service/
protocol were created out of a merger of "computer system" ideas and the
CCITT's "Telematic service" ideas (probably the specific CCITT
Recomendation was T.62 but my memory is hazy).  Some (dumb) devices
which followed the draft CCITT Recomendation were expected to generate a
"canned" response to an open request; "processing" of the response would
be done at the originating (intelligent) end.  If you think this is not
too sensible please don't flame me; I neither invented nor supported it.

Cheers,
Alex McKenzie