Help in proposing a local network of various machines

[utzoo!decvax!cca!smk at MITRE-BEDFORD]

Background--
	We have a variety of machines and operating systems that all need to
have access to the ARPANET.  As of now, we have a PDP-11/70 (UNIX) that is
connected.  We would like to connect other machines in our complex to the
ARPANET also.  We are considering some kind of local network approach, but we
have to consider a variety of machines.  For instance, we have VAX-11/780
(4.1bsd UNIX) machines, PDP-11/70 (UNIX) in addition to the one above, IBM3031
(TSO), IBM4341 (VM), various PDP-11/70's (RSX,RSTS), LISP machines, and
probably some other ones in the future.

	Because of software maintenance agreements, we can't really modify the
DEC or IBM operating systems (but I guess if we had to, we would).  Some of
the machines are too far away for DMA connections.


Question--
	Does anyone out there know of a nice way to allow these computers to
have access to the ARPANET?  We think a local area network is the way to go,
but we can be persuaded to take another approach.  It would be nice to have
remote execution (or login) on another machine, although the ARPANET issue is
central to our thinking.

	Is it feasible to have "mini-networks" of like machine--like operating
systems and form a ring between one machine of each variety?  Are there other
methods that are just as good?  If you could, I would like to hear how you
have tackled this problem for your environment (or plan to).  We would also
like to hear how solutions account for expansion of the network.


					Steve Kramer
					MITRE Corp.
					M/S B330
					PO Box 208
					Bedford, MA  01730
					smk at mitre-bedford
					617-271-3874