andys@ux1.cso.uiuc.edu (10/01/90)
I would like to get some feedback on what people think about installing SHIELDED twisted pair. I am currently doing a network design for a building that will have approx. 800 offices. The building will be used as a computer research facility. High speed networks will be required. Each room will have UTP, coax or a some combination of the two. But, I'm getting the feeling that FDDI will be supported on shielded twisted pair. 800+ runs of anything will be expensive and I am willing to bite the bullet, but which bullet? Andy Schmidt UofI
kwe@buit13.bu.edu (Kent England) (10/03/90)
In article <4200008@ux1.cso.uiuc.edu> andys@ux1.cso.uiuc.edu writes: > >I would like to get some feedback on what people think >about installing SHIELDED twisted pair. > >... >But, I'm getting the feeling that FDDI will be supported on >shielded twisted pair. 800+ runs of anything will be >expensive and I am willing to bite the bullet, but which >bullet? > > Perhaps you would be interested in FDDI on coax? I understand there is a move afoot to support that medium. I also think that fiber will be important in future, so continue to keep an eye on that technology. It is good for more than FDDI. --Kent
paul@hpsciz.HP.COM (Paul Mooney) (10/03/90)
/ hpsciz:comp.dcom.lans / andys@ux1.cso.uiuc.edu / 8:23 am Oct 1, 1990 / > I am currently doing a network design for a building that > will have approx. 800 offices. The building will be used > as a computer research facility. High speed networks will > be required. Each room will have UTP, coax or a some > combination of the two. My suggestion, for the little its worth, would be to install UTP and plan to replace all of it within the next few years with fiber. I have the feeling that fiber-to-the-cubicle will be feasible before FDDI on shielded twisted pair. But thats just a feeling. Paul Mooney ----------
jiii@sapphire.idbsu.edu (John Van Deusen - guest student) (10/04/90)
In article <4200008@ux1.cso.uiuc.edu> andys@ux1.cso.uiuc.edu writes: > I would like to get some feedback on what people think > about installing SHIELDED twisted pair. > ... > Andy Schmidt > UofI The impetus to implement FDDI on twisted pair is to try to use what already exists. For that reason, the ANSI FDDI committee might well be considering even unshielded twisted pair. In any case, 150 meters is likely to be the distance limit. I would want to run fiber between the pieces of equipment as it might be needed, without going to the hassle and expense of multiplexing into a building-wide fiber backbone that somebody had built into the building. I would prefer an office complex with the capability for adding or deleting the fiber links as they were needed. The price of fiber is plunging, so I would acquire it with the equipment that it is to connect. I wouldn't install any coax at all. -- jiii
cmilono@wet.UUCP (Carlo Milono) (10/04/90)
In article <4200008@ux1.cso.uiuc.edu> andys@ux1.cso.uiuc.edu writes: > >I would like to get some feedback on what people think >about installing SHIELDED twisted pair. Awful! If you ground *both* ends, prepare for meltdown on some runs...I am serious; the differential ground potential (ground isn't ground) can run into sufficient amperage to melt copper. >as a computer research facility. High speed networks will >be required. Each room will have UTP, coax or a some >combination of the two. UTP would be a must - coax is only necessary if you want to support broadband with the attendant, relatively complex electronics. What about installing fiber? AT&T now has a single-sheath wire that has a pair of 62.5 micron fibers and two four-pair copper. You can leave the fiber unterminated and implement as you see fit...That will provide the "F" of FDDI. > >But, I'm getting the feeling that FDDI will be supported on >shielded twisted pair. 800+ runs of anything will be >expensive and I am willing to bite the bullet, but which >bullet? > FDDI - if by that you mean 100Mbps transmission with token technology, then I would say that you are correct, but it *is* doable under UTP. The problems with 'porting' FDDI to copper media is FCC regulations, with either STP or UTP; the harmonics are such that you would need to triple or quadruple the shield in every exposed (not in conduit) piece of cable. There are committees working on the *correct* way to achieve interoperability between FDDI and what has been called CDDI, but the encoding scheme will change, so that a simple media converter will not suffice, but rather a coding-converter will be required as well. > >Andy Schmidt >UofI -- Carlo Milono UUNET: cmilono%wet.uucp (via claris/well)