3270 controller simulation
cctalk at gtaylor.tnetconsulting.net
Mon Nov 18 15:31:48 CST 2019
On 11/18/19 1:37 PM, Dave Wade via cctalk wrote:
> One thing which complicates things is that we have (roughly) layered
> protocols in place between the 3174 and the host.
I'm trying to actually map them in my head. I may have to transition to
paper / white board.
> So at the physical level we have channel attached, SDLC, Token Ring
> and bi-sync.
I think there's Ethernet in there too.
> Above that we have the channel protocols, HDLC/SDLC and bi-sync polling.
IMHO both the physical (L1 in OSI terms) and protocol (L2) are decidedly
locally significant and probably mostly agnostic to the higher layer
> Then we may have SNA (which encompasses many options) to transport the
> data through the network.
I am guessing that SNA is mostly agnostic to the lower protocols and
worries more about data movement across one or more lower layer network
> At the top the protocols and frame formats in the Data Streams manual
> which are broadly the same but with tweaks for SNA, Local and Bi-Sync.
Is this where APPN / APPC and the likes come into play? Actual
application information riding on top of SNA?
Grant. . . .
unix || die
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