Case #0:

Network scenario and constraints:

Explain how a terminal multiplexor (in this day and age) is
most likely hooked up so that say it does NOT waste precious IPv4
network addresses; i.e., a terminal mux set up as follows would
not be a boon:

			| ethernet (net 1.0.0.0)
		----------------
                |		|
		----------------
		| async port    | async port
		... phone circuits
		Host0		Host1

each async port uses one entire IP subnet
		port0:  net 2.0.0.0
		port1:  net 3.0.0.0

A typical small-end terminal multiplexor might have one ethernet port,
and 16 "async" ports, be they POTS modem lines or ISDN lines or whatever.

Of course using class A addresses here is really wasteful, as opposed
to just to a traditional class C network with 3 bytes of net and 
one byte of hosts.  But any given port by definition will only have
two IP addresses associated with it worst case, and in reality need only
have the dialup host associated with an IP address.

Remember: routing is 2 1-way problems.

So what solutions exist for making the above work in terms of routing 
and ip (and subnet) addressing?

What security problems might exist in general for such a dialup solution?