🚀 go-pugleaf

In article <H7yVwB2w164w@campbell.Gwinnett.COM>, bc@campbell.Gwinnett.COM (campbell) writes:
>   Can someone tell me which - if any - document(s) (IBM or otherwise)
>   explain the innards of DLC protocol?  SNA frames in general?
> 
     Try these two for starters:

	IBM SNA Formats GA27-3136-12 ( SNA message formats )

	IBM SNA Format & Protocol Reference Manual ( Architecture Logic ) 
	(FAPL for short)

        SC30-3112-?  ( I have -2, I'd check to see what the latest rev is )


>   There is an awful lot in both these documents but I have come
>   across some things in writing, modifying, and testing 3174 controller
>   code that I can't seem to find the answers to.  Some of these are:
>   What do I screw up if I accidentally send the host two consecutive
>   NOTIFYs?  In this case, is the reception of a sense message good
>   enough to continue or am I hosed up from then on?  (I. e, pending
>   my fixing that particular problem, is the rest of what I see okay?)
>   What do I do if the reserved bit of byte0 of the RH is set sometimes
>   and not others?  What exactly is the meaning of the DR1 bit?
>   There are more.

    1) probably not a lot whole lot, NOTIFY is a status message.

    2) Most SNA implementations don't care about the reserve bits...  it 
       doesn't hurt to explicitly clear them all though.  

    3) DR1 = Definate Response 1 Indicator - used in combination with
             DR2 and ERI to indicate what form of response is requested.
             Generally the response type should be the same type as the
             request ( If a response is sent, the DR bits should match 
             those set in the request). More on the exact working of 
             these bits can be found in the Formats manual and/or the
             FAPLs ( note there is a seperate FAPL for LU6.2 )

> 
>   For that matter, does anyone know where I can find a state
>   machine/graph/chart/whatever of what is to be returned to
>   the host depending what is received in whatever mode?  (For
>   example, an ACTLU in NRM).
> 
    If you're not in NRM, then you can't receive an ACTLU.  The state
    information for ACTLUs is in the FAPL.
    You may also want to reference an SDLC manual ( if that's what you're
    working with ) - IBM SDLC - G27-3093.

                                - Good Luck - 

 					.
  				/tony . . .
					.

	"Jazz isn't dead, it just smells funny." - FZ