lairdkb@mentor.cc.purdue.edu (Kyler Laird) (01/16/91)
I'm installing a LAN (OS/2) with a maximum spread of well under the 606' max. for thin-net. The max. number of users is <20. The network specialist here advised thick-net. As I understood, his main concern was that the BNC connections occassionally go bad or get knocked out. Is this really enough to merit the extra expense and hassle of thick-net? thanks! --kyler
davecb@yunexus.YorkU.CA (David Collier-Brown) (01/16/91)
lairdkb@mentor.cc.purdue.edu (Kyler Laird) writes: | The network specialist here advised thick-net. As I understood, his main | concern was that the BNC connections occassionally go bad or get knocked out. | Is this really enough to merit the extra expense and hassle of thick-net? For permanent, in-ceiling, long cables with machines that have thick-ethernet drop cable connectors, thicknet is ok, sort of. Individual machines may fall off the net if the drop cable connectors fail (as they do!), but the net stays up until someone whacks a tranceiver. For non-permanent, short cables, thin is ok, sort of. Machines rarely fall off the net for mechnical reasons, but people can accidentally break the whole net by disconnecting cables. We're stopped using thicknet years ago... --dave -- David Collier-Brown, | davecb@Nexus.YorkU.CA | lethe!dave 72 Abitibi Ave., | Willowdale, Ontario, | Even cannibals don't usually eat their CANADA. 416-223-8968 | friends.
henry@zoo.toronto.edu (Henry Spencer) (01/17/91)
In article <3832@mentor.cc.purdue.edu> lairdkb@mentor.cc.purdue.edu (Kyler Laird) writes: >The network specialist here advised thick-net. As I understood, his main >concern was that the BNC connections occassionally go bad or get knocked out. > >Is this really enough to merit the extra expense and hassle of thick-net? Depends very much on the environment. Thick Ethernet is, indeed, much more robust, partly because your network does not run right to the back of each user's machine where it can be jerked around or disconnected at his whim. The price you pay for thin Ethernet's convenience and low cost is much greater vulnerability to network disruption if your environment is not well controlled. If your users know what they're doing and can be trusted to treat your cable with respect, or are unsophisticated enough that they treat all hardware with respect, thin should be fine. Otherwise, consider thick or twisted-pair (which runs separate cable from each user's box to a central hub where faults can be isolated). We use thin within our machine room, but plan to go with twisted pair if/when we start doing Ethernet to users' offices. -- If the Space Shuttle was the answer, | Henry Spencer at U of Toronto Zoology what was the question? | henry@zoo.toronto.edu utzoo!henry
cornutt@freedom.msfc.nasa.gov (David Cornutt) (01/17/91)
It's no accident that most professional video gear is wired with BNC connectors. They're quite robust. -- David Cornutt, New Technology Inc., Huntsville, AL (205) 461-6457 (cornutt@freedom.msfc.nasa.gov; some insane route applies) "The opinions expressed herein are not necessarily those of my employer, not necessarily mine, and probably not necessary."
stacy@sobeco.com (s.millions) (01/19/91)
lairdkb@mentor.cc.purdue.edu (Kyler Laird) writes: >The network specialist here advised thick-net. As I understood, his main >concern was that the BNC connections occassionally go bad or get knocked out. >Is this really enough to merit the extra expense and hassle of thick-net? I have seen more problems with transceiver cables than with bnc plugs. Note that unless the device you are plugging into the net is equipped for thin, you are still going to have the transceiver cable problems. Most of the problems I have seen with BNC connectors have been people not knowing how to disconnect something from the net without taking disturbing the net. I like the "AMP Fast Tap" (I'm sure something in there is a trade mark of someone) connectors for that. Short of ripping the entire connector out of the wall, it is fairly safe from naive users. -stacy -- "Sorry I had to plug you mister duck, but I'm a sportsman." stacy@sobeco.com - Almyer Fudd uunet!sobeco!stacy
spurgeon@.uucp (Charles E. Spurgeon) (01/19/91)
In article <BOB.91Jan16225107@volitans.MorningStar.Com> bob@MorningStar.Com (Bob Sutterfield) writes: >In article <3832@mentor.cc.purdue.edu> lairdkb@mentor.cc.purdue.edu (Kyler Laird) writes: > ...BNC connections occassionally go bad or get knocked out. > >I have *far* fewer problems with well-made BNC cable ends than with >those infernal slidey-clippy bent sheet metal things that thick >Ethernet transceiver cables use to try to hold themselves to their >terminals. Thin, flexible cables with BNC connectors are much more >forgiving of equipment movement and cable abuse in users' offices. If >you decide you must go with thick transceiver cables, at least get >some of the modification kits to retrofit them with positive >screwdowns. We recently purchased some office transceiver cables from Cabletron, and I noticed that the sliding latch on these cables had been redesigned to the point where they work much better. (An office transceiver cable is a lighter weight, shorter distance version of the standard Ethernet transceiver cable.) It's too hard to show in ASCII graphics, but basically the ends of this new sliding latch assembly are physically attached to a raised edge of metal along both long sides of the latch. This means that the weakest portion of this assembly, and the one that used to bend easily, is now fixed in place. The result is that when this sliding latch is attached to a correctly assembled set of mating posts (located on the male end of the 15 pin connector) the connection is much more solid. I hasten to note that a "correctly assembled set of mating posts" can be hard to find on some equipment, notably Sun 3s. I was pleased to see this bit of engineering. The latch has a solid detent feel to the side-to-side motion now, and connections between these cables and transceivers are solid and don't give us any problems. Charles E. Spurgeon | spurgeon@emx.utexas.edu | University of Texas at Austin | ...!cs.utexas.edu!ut-emx!spurgeon| -------------------------------------------------------------------------
bruce@camb.com (Barton F. Bruce) (01/29/91)
In article <BOB.91Jan16225107@volitans.MorningStar.Com>, bob@MorningStar.Com (Bob Sutterfield) writes: > > I have *far* fewer problems with well-made BNC cable ends than with > those infernal slidey-clippy bent sheet metal things that thick very true > If you decide you must go with thick transceiver cables, at least get > some of the modification kits to retrofit them with positive > screwdowns. If you must use tranceiver cable at all, use the 'office' grade that is almost as thin as thin-net coax, and that 1) has higher loss so it can't be terribly long, but most important: 2) is so limp that the flimsy slide latches are adequate to hold it in place! If you 'own' lots of tranceivers using the fairly standard AMP vampire tap head, buy new heads to convert to BNC. I prefer the ones with a single BNC rather than the ones with the integral T and 2 BNCs, so an external T is necessary. Then removal from the line is easy without trashing others on that segment. AMP tranceiver heads: (I think the BNC ones are about $17 - bought 'right') vampire 228752-1 BNC - T 221918-1 BNC single 222455-1 ( best choice for thin-net use) N - T 221914-1 (N is the connector at the end of Ether-HOSE)