Re: Milking machines


Walt Haas (haas@gr.utah.edu)
23 Sep 88 21:20:45 GMT


Roger Fajman (RAF@NIHCU.BITNET) writes:

> ...We currently have a Bridge CS/1 with 32 ports that is hooked up to our
> IBM mainframe as a milking machine... Our biggest complaint about the
> Bridge CS/1 is that it does not negotiate the Telnet option correctly. It
> says that it will echo and then expects the host to do it. The problem is
> that our host does not echo, so the user must manually turn on echoing at
> their end...

We received from 3com/Bridge a model CS/1 running release 20000 of their
TCP software for evaluation. When I TELNET to it from cs.utah.edu, a
VAX 8600 running 4.3 BSD, the following actual TELNET parameter negotiation
occurs (as observed with an Ethernet monitor):

CS/1: WILL SUPPRESS-GO-AHEAD DO SUPPRESS-GO-AHEAD WILL TRANSMIT-BINARY
      DO TRANSMIT-BINARY WILL ECHO

VAX: DO SUPPRESS-GO-AHEAD WILL TERMINAL-TYPE

CS/1: DONT TERMINAL-TYPE

VAX: WILL SUPPRESS-GO-AHEAD DONT TRANSMIT-BINARY WONT TRANSMIT-BINARY
      DO ECHO

VAX: WONT TERMINAL-TYPE

The TELNET ECHO option negotiated here indicates that the CS/1 end of
the connection will be responsible for any necessary echoing of keystrokes
received from the VAX. In our configuration, the host which is being
milked by the CS/1 (a Zenith Z-LAN 500 NCU) does the actual echoing, which
is exactly as we want it. If however we were milking a host which was
not able to echo for some reason, then we would need to be able to tell
the CS/1 to send WONT ECHO in the initial TELNET parameter negotiation,
which would have the effect of forcing the VAX to echo. In my study of
the User's Guide for the CS/1 I failed to find a way to get the CS/1
to do this (that doesn't mean the CS/1 *can't* do this, of course, just
that I couldn't figure out the magic words :-).

Cheers -- Walt Haas Cheers -- Walt Haas haas@cs.utah.ed utah-cs!haas



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