🚀 go-pugleaf

Greetings,

I am in the process of implementing the ISO presentation protocol and I am
having some trouble understanding the rules to follow for the different
User-Data encodings.  I have been following Rose's "The Open Book" and
reading the CCITT docs (X.226/X.216).

As best as I can gather, I use the Simply-encoded-data alternative when:

    (1) all presentation data values are from the default context, or
    (2) the DCS contains only one context (and the context mgmt function
	unit is not active.

and I use Fully-encoded-data otherwise.


Question1

When setting up the User-data portion of a P-Connect PPDU, I don't really have 
the DCS nailed down yet (the DCS is the result of the negotiation which takes 
place at connection setup).  Do I use my proposed context(s) in lieu of the 
DCS to determine whether to use the Simple or Fully encoded alternative?

Question2

Am I correct that the transfer syntax I use to encode the presentation data 
value(s) is that syntax specified in the DCS corresponding to the PCI contained 
within the PDV?  If so, then the answer to question 1 is very important to me, 
since in the P-Connect PPDU I may be proposing multiple transfer syntaxes.  
How am I to know which syntax to use?  Or do I always use BER?


I hope I have provided sufficient information in my questions.  Any help
would be greatly appreciated.

best regards,
mb
-- 
Mark Boolootian		booloo@llnl.gov		+1 510 423 1948