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.
Yep.
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.
*nod*
I think there's Ethernet in there too.
Above that we have the channel protocols, HDLC/SDLC and bi-sync polling.
ACK
IMHO both the physical (L1 in OSI terms) and protocol (L2) are decidedly
locally significant and probably mostly agnostic to the higher layer
network.
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
links.
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
