elvy%mbcrr@HARVARD.HARVARD.EDU.UUCP (05/11/87)
We have had TCP/IP running over telephone lines for some time, now, but it doesn't exactly conform to your specs. A server runs on each end of the telephone line, alternately (randomly) waiting for a call or attempting to make one. Once a connection is established, another process is run. When that process finishes, or when the connection is lost, the server hangs up the phone and attempts to re-establish the connection. As the "process", we use a program that keeps the line open (the server sets stdin and stdout to be the telephone line before execing the new process) and keeps it in SERIAL TCP line discipline (see kernel mods I sent to this mailing list in January 1984). In addition, we ifconfig the serial interface and route packets over it. Crude in concept, perhaps, but we have had a reliable Internet connection running more-or-less all the time for the past year over a distance that precludes normal cable connections and for a fraction of the cost of leased lines. Marc (elvy@mbcrr.harvard.edu)
ROODE@BIONET-20.ARPA (David Roode) (05/13/87)
There must be something else to your story, or else the tariffs differ greatly from what I am used to. In California, a switched telephone line costs ~$15 per month with the FCC surcharge, but keeping it connected 24 hours a day would cost in usage charges an additional $300 per month. Leased lines can be had for $40 per month over distances up to 5 miles or so at least. Leased lines are 4-wire circuits and as a result I'd say the modems tend to be slightly more economical than those suitable for the dial network. What makes your situation different? -------