doug@psy.uwa.oz.au (Doug Robb) (05/13/91)
A friend of mine works in a building that has two segments
of thin wire ether-net on each floor (there are 3 floors)
and a thick wire ethernet running up the riser between
floors. Each thin wire segment runs back to the riser on
each floor. What he would like to know is what needs to be done
to make this cabling functional and the likely cost.
(thin) (thin)
floor 1 -------------------1 || --------------2
|| T
floor 2 -------------------1 || H --------------2
|| I
floor 3 -------------------1 || C --------------2
|| K
Can anybody add anything to my suggestions below?
1. terminate each end of the thick wire (cost?)
2. terminate the ends of each thin wire segment with bnc connectors
(cost = 6 x a few dollars )
3. for each thin wire tap into the thick wire backbone you
would need a transceiver. Cost ( 6 x $300 to $400 dollars?)
4. Now the bit I'm not sure of. On each floor one could run
a drop cable to a multiport repeater (eg dempr) and simply
plug the two segments into the repeater. But the only demprs
I've seen have eight ports (to run up to 8 segments) so this
would seem to be an over kill especially when multiport repeaters
are about $A4,000 each last time we got one. Are there multiport
repeaters for 2 or 4 segments? What do they cost?
Or am I barking up the wrong tree altogether, is there
a better way to connect each thin wire segment to the
thick wire? Do I need any more hardware?
Thanks,
doug@psy.uwa.oz.auhenry@zoo.toronto.edu (Henry Spencer) (05/14/91)
In article <1991May13.085357.4785@uniwa.uwa.oz> doug@psy.uwa.oz.au (Doug Robb) writes: > Or am I barking up the wrong tree altogether, is there > a better way to connect each thin wire segment to the > thick wire? Do I need any more hardware? The only way to connect thin to thick is end to end. You can't connect a thinwire segment to the middle of a thickwire segment. Ethernet cable is a bus, not a tree -- it can't branch. The only way to hook cables together at other than their ends is with a repeater of some flavor. The simplest way to do what you want is to forget the central thick segment entirely and run the ends of the thin segments to a single multiport repeater at some central point. -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry
ta1@ra.MsState.Edu (Terry Arnsdorff) (05/14/91)
If each thin-wire segment has it's own server, add an additional NIC to each server. From that card run a Transceiver cable to a Transceiver tapped to the Thick-Net. This would be cheaper in the long run than thick-to-thin repeaters, which would be another method.
bambi@kirk.nmg.bu.oz.au (David J. Hughes) (05/14/91)
From article <1991May13.170657.4786@zoo.toronto.edu>, by henry@zoo.toronto.edu (Henry Spencer): > The only way to connect thin to thick is end to end. You can't connect > a thinwire segment to the middle of a thickwire segment. Ethernet cable > is a bus, not a tree -- it can't branch. The only way to hook cables > together at other than their ends is with a repeater of some flavor. Correct yet not correct. The overall structure of the Ethernet must be a bus, but there are ways of introducing "stars" grafted onto the bus. The set-up we use here is ........... | _ Thin Thin _ | | | |====== =======| | | Thick |::| |====== =======| |::| Thick Spine | |_|====== =======|_| | Spine | | | | | Router | \ __ / \_____________| |_______________/ |__| | ________|__________ (___________________) Fibre Ring \ \ To another building The Star configuration is maintained by a Multi-Port repeater (we use 3Com / Bridge). This setup is repeated in every building on campus and there is a pair of multi-repeater on every floor of every building. To answer the original question, Yes you can do it this way but you will be up for the $A4,000 per multi-port as I have not come accross any 2 or 4 port boxes. > The simplest way to do what you want is to forget the central thick segment > entirely and run the ends of the thin segments to a single multiport > repeater at some central point. This does not help if you are using the thick to overcome a distance problem (Hence the approx 10 KM of fibre in our setup.) Bambi +----------------------------------------------------------------------------+ | David J. Hughes (AKA bambi) | bambi@kirk.bu.oz.au | | Senior Systems Programmer | bambi@kirk.bu.oz.au@uunet.uu.net | | Comms Development & Operations | ..!uunet!munnari!kirk.bu.oz.au!bambi | | Bond University, Gold Coast | Phone : +61 75 951450 | | Queensland, Australia 4229 | Fax : +61 75 951456 | +----------------------------------------------------------------------------+
brunetti@alw.nih.gov (Jim Brunetti) (05/14/91)
In article <1991May14.193206.3692@waikato.ac.nz>, hamish@waikato.ac.nz writes: |> > To answer the original question, Yes you can do it this way but you will |> > be up for the $A4,000 per multi-port as I have not come accross any 2 or |> > 4 port boxes. |> > |> |> I believe DEC sell 2,4 and 8 port repeaters. However above 8 ports I have been |> told that it is cheaper to buy a multiport repeater cage and just add ports |> when you need them. |> |> ============================================================================== |> | Hamish Marson <h.marson@waikato.ac.nz> | |> | Computer Support Person, Computer Science Department | |> | University of Waikato | |> |Disclaimer: Anything said in this message is the personal opinion of the | |> | finger hitting the keyboard & doesn't represent my employers | |> | opinion in any way. (ie we probably don't agree) | |> ============================================================================== Cabletron makes a 2 port thick to thin repeater (1 AUI, 1 BNC). Model MR2000C. -- ___________ jim brunetti brunetti@alw.nih.gov
chw@hpctdlb.HP.COM (Charlie Whiteside) (05/14/91)
>If each thin-wire segment has it's own server, add an additional NIC to each >server. From that card run a Transceiver cable to a Transceiver tapped to the >Thick-Net. This would be cheaper in the long run than thick-to-thin repeaters, >which would be another method. Segmenting the network at this point can have some great benefits. I would highly recommend putting in store and forward bridges from each server segment to the Thick backbone. This will allow better utilization on the independant (now) subnets and also allow fast problem isolation and operation of most segments in the event of a faulure on a particular segment. =============================================== Thick Lan B B B Bridges | | | Server segments | | | | | | | | | | | | I have seen networks where segmentation was not done. They worked fine with low utilizations. As they became more integrated and relyed upon the traffic levels picked up. Then a failure would take down everyone at the same time. Good Luck Charlie .
hamish@waikato.ac.nz (05/15/91)
> To answer the original question, Yes you can do it this way but you will > be up for the $A4,000 per multi-port as I have not come accross any 2 or > 4 port boxes. > I believe DEC sell 2,4 and 8 port repeaters. However above 8 ports I have been told that it is cheaper to buy a multiport repeater cage and just add ports when you need them. ============================================================================== | Hamish Marson <h.marson@waikato.ac.nz> | | Computer Support Person, Computer Science Department | | University of Waikato | |Disclaimer: Anything said in this message is the personal opinion of the | | finger hitting the keyboard & doesn't represent my employers | | opinion in any way. (ie we probably don't agree) | ==============================================================================
lee@locus.com (Lee Slaughter) (05/15/91)
In article <1991May13.170657.4786@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >In article <1991May13.085357.4785@uniwa.uwa.oz> doug@psy.uwa.oz.au (Doug Robb) writes: >> Or am I barking up the wrong tree altogether, is there >> a better way to connect each thin wire segment to the >> thick wire? Do I need any more hardware? > >The only way to connect thin to thick is end to end. You can't connect >a thinwire segment to the middle of a thickwire segment. Ethernet cable >is a bus, not a tree -- it can't branch. The only way to hook cables >together at other than their ends is with a repeater of some flavor. > uh uh...we've done it. we have mostly thick and hooked up a small net on thin to the thick using transceiver and fanout. .....thin net.......transceiver.......fanout......thick net or something like that. it worked fine. i can look up the details, if you want. just have to be sure everything (thin) is properly terminated, using a "T" on the transceiver as well. (if i recall...)
lee@locus.com (Lee Slaughter) (05/15/91)
In article <3021@kirk.nmg.bu.oz.au> bambi@kirk.nmg.bu.oz.au (David J. Hughes) writes: > >To answer the original question, Yes you can do it this way but you will >be up for the $A4,000 per multi-port as I have not come accross any 2 or >4 port boxes. > no, somebody makes two port... damn... can't remember and too lazy to look thru all catalogs, but it is somebody we use around here...TCL, CentreCOM, IsoLan, ... if you really want to know and nobody else has positively responded let me know.
henry@zoo.toronto.edu (Henry Spencer) (05/15/91)
In article <24384@dice.la.locus.com> lee@locus.com (Lee Slaughter) writes: >>... Ethernet cable >>is a bus, not a tree -- it can't branch. The only way to hook cables >>together at other than their ends is with a repeater of some flavor. >> >uh uh...we've done it. we have mostly thick and hooked up a >small net on thin to the thick using transceiver and fanout. > > >.....thin net.......transceiver.......fanout......thick net > >or something like that. it worked fine. i can look up the >details, if you want... I'd very much appreciate details of this, because I'd be very surprised to see it work the way you've described. The transceiver's non-coax end is an AUI connector. If by a "fanout" you mean a multi-AUI transceiver, same thing there. And you can't connect two AUI connectors back to back. The only way I can make sense of your diagram is to assume that either the "transceiver" or the "fanout" is really a repeater. -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry
waugh@rtpnet05.rtp.dg.com (Matthew Waugh) (05/16/91)
In article <24391@oolong.la.locus.com> lee@locus.com (Lee Slaughter) writes: >no, somebody makes two port... damn... can't remember and too >lazy to look thru all catalogs, but it is somebody we use around >here...TCL, CentreCOM, IsoLan, ... if you really want to know and >nobody else has positively responded let me know. It's CenterCOM, and also Garrett Communications, Inc., (408)980-9752 or (408)980-1654 make one. Mat Matthew Waugh waugh@dg-rtp.dg.com RTP Network Services {world}!mcnc!rti!dg-rtp!waugh Data General Corp. RTP, NC. (919)-248-6344
rmilner@zia.aoc.nrao.edu (Ruth Milner) (05/16/91)
In article <3021@kirk.nmg.bu.oz.au> bambi@kirk.nmg.bu.oz.au (David J. Hughes) writes: >From article <1991May13.170657.4786@zoo.toronto.edu>, by henry@zoo.toronto.edu (Henry Spencer): >> The only way to hook cables >> together at other than their ends is with a repeater of some flavor. > >Correct yet not correct. >The set-up we use here is ........... [ diagram deleted ] > >The Star configuration is maintained by a Multi-Port repeater ^^^^^^^^^^^^^^^^^^^ How does this differ from what Henry said? The point is, you can't hook the cables together without a box somewhere in between. Whether you have one box for each thinwire segment, or one for many, is irrelevant. You still need something with some intelligence to join them. Multi-port repeaters have that intelligence: they are proper repeaters, and most of the ones available on the market also do fault isolation on the thin segments, which is quite useful. I think Cabletron might make a repeater with less than 8 ports, but in any case, unless you are severely constrained by distance limits, you probably want room to add new segments later. Remember that the whole kit and caboodle will count as a single Ethernet and every segment will see all of every other segment's traffic - unless you do some judicious bridging/gatewaying between them instead of just repeaters. If those thinwires have workstations etc. on them, you could load up your network *very* quickly. Make sure you plan for this. -- Ruth Milner Systems Manager NRAO/VLA Socorro NM Computing Division Head rmilner@zia.aoc.nrao.edu
bob@pirates.UUCP (Bob Fawcett) (05/16/91)
Allied telesis makes a line of multi-port repeaters with a combination of thin and AUI ports. They are available in 2,4,5,and 9 port configurations. The 2 can be any combination of thick and thin, the 4 is a 2 and 2 combo,and the 5 and 9 are 1AUI and the rest thin for 1 4 and 1 8 setups. We use them on our campus and have been pleased with performance and reliability thus far. Bob Fawcett | bob@pirates.armstrong.edu | Internet Academic Computing | bob@pirates.uucp | UUCP Armstrong State College | 11935 Abercorn Street | Savannah, GA 31419
cosheff@bitcave.in-berlin.de (Charles O. Shefflette) (05/19/91)
rmilner@zia.aoc.nrao.edu (Ruth Milner) writes: >In article <3021@kirk.nmg.bu.oz.au> bambi@kirk.nmg.bu.oz.au (David J. Hughes) writes: >>From article <1991May13.170657.4786@zoo.toronto.edu>, by henry@zoo.toronto.edu (Henry Spencer): >>> The only way to hook cables >>> together at other than their ends is with a repeater of some flavor. >> >>Correct yet not correct. >>The set-up we use here is ........... >[ diagram deleted ] >> >>The Star configuration is maintained by a Multi-Port repeater > ^^^^^^^^^^^^^^^^^^^ >How does this differ from what Henry said? >The point is, you can't hook the cables together without a box somewhere in >between. Whether you have one box for each thinwire segment, or one for many, >is irrelevant. You still need something with some intelligence to join them. >Multi-port repeaters have that intelligence: they are proper repeaters, and >most of the ones available on the market also do fault isolation on the thin >segments, which is quite useful. Well, that isn't exactly true, either. According to the 3COM and to the Cabletron manuals we have, the only thing you really have to do to connect thin- and thick-wire ethernet together is to use the appropriate adapter connector between them. You do have to be certain that you don't exceed the cable length restrictions for the thin-wire when you make the connection, but other than that you don't really have any problems with them. The transcievers are identical except for the actual tap onto the net, so the ethernet cards, etc. won't even know or care what they are physically connected to. In our case we have just this configuration, a thickwire system with some thinwire connected to it with type N to BNC adapters. In the system we have about 50 workstations connected and experience no problems with the network except for the occasional failed transciever. Our network map looks something like this: #=======#=============# #==============#========#========#===== | | | | | | | Server | Fiber Repeater Repeater Repeater Repeater | | | | | | | ========#===------- ===#== ==#=== ==#=== ... etc... where: === is thick ethernet --- is thin ethernet # is an ethernet tap This doesn't actually depict our real layout, it's lots more complex than that, but you should get the general idea. -- ============================================================================= Chuck Shefflette cosheff@bitcave.in-berlin.de System Engineer (cosheff@netmbx.in-berlin.de) ManTech FEC, Berlin Germany
rmilner@zia.aoc.nrao.edu (Ruth Milner) (05/21/91)
In article <1991May18.231445.18574@bitcave.in-berlin.de> cosheff@bitcave.in-berlin.de (Charles O. Shefflette) writes: >rmilner@zia.aoc.nrao.edu (Ruth Milner) writes: > >>In article <3021@kirk.nmg.bu.oz.au> bambi@kirk.nmg.bu.oz.au (David J. Hughes) writes: >>>From article <1991May13.170657.4786@zoo.toronto.edu>, by henry@zoo.toronto.edu (Henry Spencer): >>>> The only way to hook cables >>>> together at other than their ends is with a repeater of some flavor. >>> >>>Correct yet not correct. >>>The Star configuration is maintained by a Multi-Port repeater >> ^^^^^^^^^^^^^^^^^^^ >>How does this differ from what Henry said? >>The point is, you can't hook all the cables together without a box somewhere >>in between. > >Well, that isn't exactly true, either. According to the 3COM and to the >Cabletron manuals we have, the only thing you really have to do to >connect thin- and thick-wire ethernet together is to use the appropriate >adapter connector between them. Sure - *at the ends of the cable*. Not in the middle. That's precisely what was said to start with (see above - note the phrase "at other than their ends"). >#=======#=============# #==============#========#========#===== >| | | | | | | >Server | Fiber Repeater Repeater Repeater > Repeater | | | > | | | | >========#===------- ===#== ==#=== ==#=== ^^^^^ The only piece of thinwire shown here is connected at the *end* of a piece of thickwire. Summary: At each end of the cable, you can connect a single cable with the appropriate adapter - provided you don't exceed length/connection specs. If, however, you need to make a connection in the middle of the thick cable, or you need to connect more than one piece of the other cable (like a Y or a star), or you will be exceeding specs, you *have* to have a box in between. This is all dictated by the fact that Ethernet is a multidrop topology, not a star or branch. Pure cable can only be linear. From what I recall of the original poster's situation, he has several floors spanned by a vertical thickwire. So it stands to reason that he is not going to be able to connect all of those floors by thinwire at the ends of the thickwire. Therefore, he *must* put something in between. Period. -- Ruth Milner Systems Manager NRAO/VLA Socorro NM Computing Division Head rmilner@zia.aoc.nrao.edu
graeme@ccu1.aukuni.ac.nz ( Graeme Moffat) (05/24/91)
waugh@rtpnet05.rtp.dg.com (Matthew Waugh) writes: >In article <24391@oolong.la.locus.com> lee@locus.com (Lee Slaughter) writes: >>no, somebody makes two port... damn... can't remember and too >or (408)980-1654 make one. IMC Networks Corp, Tustin CA 800-624-1070 have a unit with 1 AUI & 1 BNC fixed, & up to 6 cards as wanted, either 2xBNC, 1xFOIRL, or 2xTP - it's called a PC-Nic basket & is well priced. -- Graeme Moffat g.moffat@aukuni.ac.nz \ Time wastes us all, Computer Aided Design Centre, Fax: +64-9-366-0702 / our bodies & our wits School of Engineering, Ph: +64-9-737-999 x8384 / But we waste time, University of Auckland, Private Bag, Auckland, NZ \ so time & we are quits
mad@media03.UUCP (Martin Admiraal) (05/30/91)
In article <24391@oolong.la.locus.com> lee@locus.com (Lee Slaughter) writes: >In article <3021@kirk.nmg.bu.oz.au> bambi@kirk.nmg.bu.oz.au (David J. Hughes) writes: >>To answer the original question, Yes you can do it this way but you will >>be up for the $A4,000 per multi-port as I have not come accross any 2 or >>4 port boxes. >no, somebody makes two port... damn... can't remember and too >lazy to look thru all catalogs, but it is somebody we use around >here...TCL, CentreCOM, IsoLan, ... if you really want to know and >nobody else has positively responded let me know. I'm sure that Cabletron makes four and eight port repeaters. Last year we sold them to for resp. plm. DM 8500 and DM 15000. -- +--------------------+------------------------+----------------------+ | Martin Admiraal | EMAIL mad@media01.uucp | | | Mediasystemen B.V. | ..!hp4nl!media01!mad | I'm going slightly | | PO Box 4932 | | MAD | | 2003 EX HAARLEM | Phone +31 23 319075 | oh, dear | | The Netherlands | Fax +31 23 315210 | - Freddy M. & Queen -| +--------------------+------------------------+----------------------+ -- +--------------------+------------------------+----------------------+ | Martin Admiraal | EMAIL mad@media01.uucp | | | Mediasystemen B.V. | ..!hp4nl!media01!mad | I'm going slightly | | PO Box 4932 | | MAD | | 2003 EX HAARLEM | Phone +31 23 319075 | oh, dear | | The Netherlands | Fax +31 23 315210 | - Freddy M. & Queen -| +--------------------+------------------------+----------------------+
a_steiner@nwu.edu (Albert Steiner) (06/04/91)
In article <2348@media03.UUCP> mad@media03.UUCP (Martin Admiraal) writes: > >no, somebody makes two port... damn... can't remember and too > >lazy to look thru all catalogs, but it is somebody we use around > >here...TCL, CentreCOM, IsoLan, ... if you really want to know and > >nobody else has positively responded let me know. INMAC sells repeaters made by Allied Telesis (2 Thin, 2 thick ports). They are working for us and less price than other solutions. ----------------------------------------- a_steiner@nwu.edu Albert Steiner, Academic Computing and Networking, Northwestern University, Evanston, IL 60208 708-491-4056
a_steiner@nwu.edu (Albert Steiner) (06/04/91)
<3021@kirk.nmg.bu.oz.au> <24391@oolong.la.locus.com> <2348@media03.UUCP> Organization: Northwestern University, ACNS In article <2348@media03.UUCP> mad@media03.UUCP (Martin Admiraal) writes: > >no, somebody makes two port... damn... can't remember and too > >lazy to look thru all catalogs, but it is somebody we use around > >here...TCL, CentreCOM, IsoLan, ... if you really want to know and > >nobody else has positively responded let me know. INMAC sells repeaters made by Allied Telesis (2 Thin, 2 thick ports). They are working for us and less price than other solutions. ----------------------------------------- a_steiner@nwu.edu Albert Steiner, Academic Computing and Networking, Northwestern University, Evanston, IL 60208 708-491-4056 ----------------------------------------- a_steiner@nwu.edu Albert Steiner, Academic Computing and Networking, Northwestern University, Evanston, IL 60208 708-491-4056
scott@pita.cns.ucla.edu (Scott Burris) (06/05/91)
In article <1991Jun4.155323.6688@casbah.acns.nwu.edu> a_steiner@nwu.edu (Albert Steiner) writes: >In article <2348@media03.UUCP> mad@media03.UUCP (Martin Admiraal) writes: >> >no, somebody makes two port... damn... can't remember and too >> >lazy to look thru all catalogs, but it is somebody we use around >> >here...TCL, CentreCOM, IsoLan, ... if you really want to know and >> >nobody else has positively responded let me know. >INMAC sells repeaters made by Allied Telesis (2 Thin, 2 thick ports). >They are working for us and less price than other solutions. > >----------------------------------------- >a_steiner@nwu.edu >Albert Steiner, Academic Computing and Networking, >Northwestern University, Evanston, IL 60208 >708-491-4056 We've had some problems with Allied Telesis equipment in this kind of service (thick to thin connects) on an ethernet near the distance limit causing lots of collisions. We put a Cabletron unit in (admittedly more expensive) and have had no more problems. -- ---------- Scott Burris UCLA Campus Network Services cnetslb@oac.ucla.edu (213) 206-4860 - OR - scott@pita.cns.ucla.edu
bruce@camb.com (Barton F. Bruce) (06/06/91)
In article <1991May13.085357.4785@uniwa.uwa.oz>, doug@psy.uwa.oz.au (Doug Robb) writes: > > A friend of mine works in a building that has two segments > of thin wire ether-net on each floor (there are 3 floors) > and a thick wire ethernet running up the riser between > floors. Each thin wire segment runs back to the riser on > each floor. What he would like to know is what needs to be done If you truely ONLY need 2 segments per floor, and IF there are only 3 floors, and if you are not stretched to the outer end of your 185 meter thin segment limit already, THEN totally eliminate the Etherhose backbone. You can easily stick it in later if necessary. True that suitable repeaters come in 1 or 8 ports typically (DESPR , DEMPR) and the 1 port ones are SO expensive and limiting you always buy the 8 port one because over its life it will be redeployed and you will need more ports. So get 1 (only) DEMPR. Stuff the green-eyed loop back plug into its AUI port to turn it into your backbone in a box. Mount it on the middle floor. Run your loops from there. The DEMPR has a terminator built in, so you can't go 2 ways using a T, and you can't use a T and add a second terminator. You just plug one cable end in. The returning far end of the cable is 'nice' if you can afford the length (not $s, this stuff is cheap, but you are only allowed 185 meters per segment). That far end MUST end in a 50 ohm terminator. But, with it physically back at the closet, and with only 6 of 8 ports used, if some segment gets broken in some wall, feed BOTH ends of the old segment from DEMPR ports, and terminate the 2 new shorter segments after the last connected computer in each effectively cutting out the broken segment. At such time as you need a DEMPR per floor, I would buy 3 mini tranceivers that now LIST for $125, and that plug right onto the AUI connector - no AUI cable needed. These have a BNC connector and you stick a T on each, run thin net between the floors, and terminate the ends. For 3 floors thin net is fine as a backbone. It is fine at 10 floors or 20 floors, even. By the time you might start looking at ether-hose, you probably should be into some fiber solutions! Many folks NEVER use thick ethernet these days. NEVER use RG58 stuff, use the premium Belden 9907 or 89907 if you are rich or NEED Teflon.