Path: utzoo!telecom-request Date: Thu, 25 Apr 1991 18:44:12 GMT From: Mark Fulk Newsgroups: comp.dcom.telecom Subject: Re: Decreasing Costs of Transmission Message-ID: Organization: Computer Science Department University of Rochester Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 306, Message 1 of 6 Lines: 69 In article james@cs.ualberta.ca (James Borynec) writes: > 1) The costs of long distance transmission of information is going WAY > DOWN. This is because of the incredible bandwith of fiber. You can > easily fit one million phone calls onto one 32 strand fiber cable. I don't think you've absorbed the real effect of this yet. I just talked to an optics professor here, who does research into linear optical amplifiers for fiber repeaters. It is now feasible to transmit more than 100 terabits/sec on a fiber; linear optical amplifiers allow up to about 6 Tb/sec even on transoceanic cables. AT&T and NTT just signed a contract to use these fibers (probably at a lower rate at first) in a trans-Pacific cable, and the next trans-Atlantic cables will also use this technology. These cables are slated for service in about 1995. Now a phone call takes about 32 kb/s; let's say 50 kb/s to make the math easier (note: this is not using any kind of fancy compression). 20 phone calls take 1 Mb/s (actually, T1 line at 1 Mb/s handles 32 calls, I think); so 1 Tb/s is 20,000,000 calls. So a trans-oceanic cable consisting of two fibers (one each way) could handle about 120,000,000 calls. In other words, nearly half the people in the US could be talking to people in Asia using those two fibers. > 2) The real costs of transmission is really in the multiplexing > technology. Getting information on and off these fiber highways is > the cost bottleneck. Fortunately, we can build bigger, faster, and > CHEAPER multiplexers with the new silicon (and other) technologies. > Thus these costs are going down quickly too! Actually, you want to do your multiplexing optically too. This is getting easier all the time. How do you think they TESTED those fibers at the high throughputs? The hardest problem arises in connection with packet-switched networks: the last record I heard for packet switches is a degree-32 node handling 150 Mb/s on each connection; it was from BellCore and is called the ``switching fabric.'' The importance of this kind of switching technology might well be mooted by increasing bandwidth: if fibers reach 2000 Tb/s, very much in reach in view of the above, than 200-fiber cables would permit a billion global broadcast HDTV channels. > Because these costs are going down so very much they will quickly be > dwarfed (or indeed may already be dwarfed) by other costs such as > local access, accounting of calls, etc. Therefore, for all practical > purposes a LOCAL phone calls costs as much as a LONG DISTANCE phone > call. Th1e costs will be: subscriber equipment, network interfaces, and right-of- way for cables on land. > Clearly the pricing structures do not reflect these costs (Yet!). My > question is - What is AT&T, MCI, Sprint, etc going to do when they can > no longer reasonably charge more than a local call? Won't this change > the industry substantially? Will North America move to a wide area > extended flat rate billing zone? > How about this - you pay Sprint $10/month to call anywhere in the USA > to talk for as long as you want. Unfortunately, the pricing structure reflects the costs of the currently installed equipment, and will continue to do so even after that equipment is obsolete. I suspect that, short of a revolution, the best we will see will be a gradual decrease, and the promise of the new transmission technologies won't be realized until 2010 or so.