Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!rutgers!brl-adm!seismo!sundc!nears!occrsh!occrsh.UUCP!tiger.UUCP!rvk From: rvk@tiger.UUCP.UUCP Newsgroups: comp.dcom.lans Subject: Re: What can you do with an existing fi Message-ID: <144000001@tiger.UUCP> Date: Sun, 8-Feb-87 03:41:00 EST Article-I.D.: tiger.144000001 Posted: Sun Feb 8 03:41:00 1987 Date-Received: Tue, 10-Feb-87 03:01:25 EST References: <5082@reed.UUCP> Lines: 82 Nf-ID: #R:reed.UUCP:-508200:tiger.UUCP:144000001:000:4760 Nf-From: tiger.UUCP!rvk Feb 8 02:41:00 1987 /* Written 11:57 pm Jan 22, 1987 by mdr@reed.UUCP in tiger.UUCP:comp.dcom.lans */ /* ---------- "What can you do with an existing fi" ---------- */ How can you set up a fiber optic LAN so that it will later be easy to use the installed fiber for other services such as video, voice traffic or whatever? We have recently installed a fiber optic "Ethernet" throughout the campus using FiberCom equipment (I'm not sure what type of fiber we're using - I can find out). I've heard some thoughts that by going with a fiber based network, we will later be able to fully exploit the potential bandwidth of the glass. Has anyone retrofitted an in-place special purpose fiber network to carry additional traffic, probably using equipment unrelated to the original? Even if the cable is multimode, wouldn't the FiberCom equipment have to specifically forward those "channels" of the cable it was not using if the whole thing were to work with independently operating equipment? I am not a fiber wizard, as you might be able to tell, but would be interested in people's (informed?) thoughts on what might be possible. Mike Rutenberg -- Reed College -- Portland, Oregon -- 503/774-9192 /* End of text from tiger.UUCP:comp.dcom.lans */ I use a lot of fiber at the AT&T Oklahoma City factory for local networking. Its a terrific medium. Unfortunately, vendors are just now starting to discover how to make use of the bandwidth. The limitations of your fiber net are determined by the electronics plugged into the ends of it. Unless you use separate fiber, you are limited to what ever Fibercom can transmit over the fiber. Local network fibers are typically 100 micron or 62.5 micron, multi or graded index, normally used with LED going up to 200 Mega bps. Fibercom probably has a fused STAR somewhere that makes the fiber a light bus which allows it to handle ethernet/IEEE 802.3. I don't know if anyone is trying to transmit full motion video over ethernet, but its an interesting idea. Uncompressed video generates about 90 Mega bps of data so it could really load a network down. Artel Communications has a 4 X 25 Mega bps (100 Mbps) fiber ring with ethernet interface boxes. These cost about $9,000 per 8 port box. Optical Data Systems of Richardson Texas is a small company who will do about anything you want. They do fiber right in my opinion. They build "dumb" boxes and use the fact that bandwidth is cheap on fiber. For example; their 32 port asynch mux goes 20 Mbps on the fiber because it doesn't try to figure out when a byte has been received, or even a bit. It simply pumps through voltage level values 256,000 per second for each data lead. AT&T is just now discovering this gaping bandwidth conduit for its datacom products and I occasionaly get funny phone calls like "What would you do with 50 or 100 Mbps if you had it?" I answer "Anything I want." Only a product manager can ask such dumb question. No one ever asks "How fast should a computer go?" but for local networks, the idea is still novel. Off-the-shelf 200 Mbps LEDs have existed for quite a while so 100 to 200 Mbps local networks are starting to appear. Naturally the smaller companies make them first. I know "broadband networks have 250 to 400 Mbps bandwidth." True, but have you ever talked, seriously, to a broadband vendor...big surprise, after all the hot air disapates, you find that "well, rf modems that go over 1 Mbps are really expensive, so most bb networks actually go around 1/4 Mbps!!! In the last year or two, 10 Mbps "ethermodems" have come out so people can run ethernet over broadband. Just ask for pricing on a 250 Mbps rf modem and watch the salesman start back-pedaling! Yeah, I know, your can use lower speed rf modems on separate frequency bands. All I can say is, as a person who has to live with local networks every day, I do not want to try and troubleshoot "harmonics" problems and other analogue impairments. I may have problems with my electronics, like everyone, but when I go to bed at night, I sleep like a baby because I know that my fiber net will not break, degrade, go out of tune, transmit or receive RFI, and etc. I am putting in a fiber based ethernet. I will put in a fiber based MAP network next year and I already have a fiber based DATAKIT asynch data switch network (over 4000 ports). Some other big names in fiber electronics are Canoga-Perkins, Fibronics , Optelcom and, of course, AT&T. Incidentally, AT&T is introducing a metro area video conferencing service called VIVID. It requires that your area be fibered already since it only compresses the video signal down to 45 Mbps. Send me unix mail if you want more fiber, fiber product or VIVID info. Ray Kellogg ihnp4!ocsmb!rvk