sean@geac.UUCP (Sean Phelan) (04/15/89)
I'm using a Motorola Delta box with a 3270/SNA emulation package to
implement a gateway into IBM hosts. Terminals on our system appear
to the IBM as 3278 terminals on a 3274 controller.
A real 3274 controller supports a maximum of 32 terminals. However
our computer has considerably more than 32 terminals on it. We could
just let every new terminal that wants to go through the gateway have
the next free 3278 emulation, up to a maximum of 32. The IBM people
don't like that, though, because they are used to identifying specific
terminals by their physical address - controller and terminal number.
So my question to the net is : Is there REALLY a limit of 32 terminal
addresses ( LUs ) on a 3270, or is it just a hardware limitation of
the original boxes, which can be ignored by software emulations ?
On a related subject, if there is anybody out there doing comms work
on the Motorola Delta boxes, especially with SNA and X.25, who would
like to share experiences/horror stories, PLEASE mail me !!
Thanks very much !!
Sean
--
Sean Phelan | "Education furnishes the mind,
Geac Computer, Markham, Ontario | making it a pleasant place to
sean@geac | spend the rest of one's life"
{uunet!mnetor,yunexus,unicus,utgpu}!geac!sean |soley@moegate.UUCP (Norman S. Soley) (04/18/89)
In article <7112@geac.UUCP> sean@geac.UUCP (Sean Phelan) writes: >I'm using a Motorola Delta box with a 3270/SNA emulation package to >implement a gateway into IBM hosts. Terminals on our system appear >to the IBM as 3278 terminals on a 3274 controller. > >A real 3274 controller supports a maximum of 32 terminals. However >our computer has considerably more than 32 terminals on it. We could >just let every new terminal that wants to go through the gateway have >the next free 3278 emulation, up to a maximum of 32. The IBM people >don't like that, though, because they are used to identifying specific >terminals by their physical address - controller and terminal number. So? why listen to them. We run an SNA Gateway under UNIX here (XICOM MicroNode under 386ix) that behaves exactly the way you describe, when you kick up a terminal emulation session you get the next available LU. All the IBM side sees is that ports 0-X are almost always busy and ports X-32 are rarely used. There is nothing in the technology to stop you from doing this, it sounds like it's your mainframe people who are the problem not IBM (I have one of these, wanted to go around putting stickers with the VTAM numbers on every PC, just couldn't get it when I tried to explain that the VTAM numbers could change, same guy also couldn't understand why he couldn't plug the keyboard from his old 3279 into his new PC). There can be limitations however introduced by applications, for security reasons some systems (like the MTO's driver licencing system) may insist that userid BHJ8890 log in only on a specific VTAM line, In that case you can probably configure the gateway to force this behavior (the XICOM can at any rate) the users love it because now they don't have to go back to their office to look up stuff, any terminal in the building gets them the same terminal ID. -- Norman Soley - The Communications Guy - Ontario Ministry of the Environment Until the next maps go out: moegate!soley@ontenv.UUCP if you roll your own: uunet!{attcan!ncrcan|mnetor!ontmoh}!ontenv!moegate!soley I'd like to try golf, but I just can't bring myself to buy a pair of plaid pants