Very Computer

Hello
        at work, we have 2 Linux machines hooked together using Coax
cables and the setup has been working great for the last few months.
we would like to add a third machine on this lan.  the problem is that
the third machine is at a distance away from the other 2.  I would
like to know if ....  it is possible to use Co-ax to hook 2 machines
together and then... link the third machine using a 10baseT cable from
it's (third machine's) either Ethernet card.. into the second machines
SMC Ultra Card.  Will this work?
        also, while we're at it.. can someone pliss tell me about the
distance limitations on a Co-ax Segment of a network?  how long cann
the total co-ax segment be?
        and finally, can someone please recommend a good book for
Network hardware issues?  

        thanks a lot.

--
Sanjay Bhatia
I'm Alive.

[snip]
: like to know if ....  it is possible to use Co-ax to hook 2 machines
: together and then... link the third machine using a 10baseT cable from
: it's (third machine's) either Ethernet card.. into the second machines
: SMC Ultra Card.  Will this work?
:       also, while we're at it.. can someone pliss tell me about the
: distance limitations on a Co-ax Segment of a network?  how long cann
: the total co-ax segment be?
:       and finally, can someone please recommend a good book for
: Network hardware issues?  

I believe the maximum distance for thinnet is 185 meters. This question
really doesn't have anyhting to do with Linux, so you might find better
answers posting to comp.dcom.ethernet. That group should be able to point
you to the Ethernet FAQ, which is an excellent place to start, IMO.

--------------------------------------------------------
        Mark Cudworth

        http://www.indy.net/~cudworth/index.html
--------------------------------------------------------

Quote:>    at work, we have 2 Linux machines hooked together using Coax
>cables and the setup has been working great for the last few months.
>we would like to add a third machine on this lan.  the problem is that
>the third machine is at a distance away from the other 2.  I would
>like to know if ....  it is possible to use Co-ax to hook 2 machines
>together and then... link the third machine using a 10baseT cable from
>it's (third machine's) either Ethernet card.. into the second machines
>SMC Ultra Card.  Will this work?

No, I don't think it will.  Most ethernet cards let you use the
coax (I assume you mean thinnet) or the 10baseT, but not both at
once.  Also, connecting 2 10baseT hosts without a hub requires
that you swap some wires in the cable.

Quote:>    also, while we're at it.. can someone pliss tell me about the
>distance limitations on a Co-ax Segment of a network?  how long cann
>the total co-ax segment be?

I think thinnet can go something like 600 feet (~200 meters).
10baseT can't go that far, I think its max is < 200 feet.  Thin
coax is a better choice to go a long distance, while Thick coax
is required to go _really_ far, like between buildings (at least
if you want to do it without repeaters).

---
 Bob Hauck                                 Wasatch Communications Group

Quote:>>        at work, we have 2 Linux machines hooked together using Coax
>>cables and the setup has been working great for the last few months.
>>we would like to add a third machine on this lan.  the problem is that
>>the third machine is at a distance away from the other 2.  I would
>>like to know if ....  it is possible to use Co-ax to hook 2 machines
>>together and then... link the third machine using a 10baseT cable from
>>it's (third machine's) either Ethernet card.. into the second machines
>>SMC Ultra Card.  Will this work?

>No, I don't think it will.  Most ethernet cards let you use the
>coax (I assume you mean thinnet) or the 10baseT, but not both at
>once.  Also, connecting 2 10baseT hosts without a hub requires
>that you swap some wires in the cable.

>>        also, while we're at it.. can someone pliss tell me about the
>>distance limitations on a Co-ax Segment of a network?  how long cann
>>the total co-ax segment be?

>I think thinnet can go something like 600 feet (~200 meters).
>10baseT can't go that far, I think its max is < 200 feet.  Thin
>coax is a better choice to go a long distance, while Thick coax
>is required to go _really_ far, like between buildings (at least
>if you want to do it without repeaters).

10Base5 means 10 Mbps, baseband, 500 meter segments; more commonly
known as Thicknet.  10Base2 means 10 Mbps, baseband, 200 meter
segments; more commonly known as thinnet.  Thinnet Coax cannot have
tees, Thicknet can; however, I've done it successfully.  10BaseT means
10 Mbps, baseband, twisted pair;  distance depends on how good your
wire is, but don't count on much.  10BaseT is the noisiest, so try to
avoid using it for backbones.  The official spec calls for no more than
4 repeaters in any network.

I once had a lab that had 1 10BaseT link to the room where I needed
several machines.  I took a 9-port hub that had 8 10BaseT connectors
and 1 coax connector (~$110.) and hooked many machines in that room to
the network via the coax.

If you want to connect buildings together, do yourself a favor and use
fiber optic cable and repeaters.  You can reuse the cable later for a
higher speed link, and the labor cost won't be repeated.

Unless, of course, you use a hub. Since these are available for
$150 these days (8 10BaseT ports + one selectable between 10Base2 and
AUI), it gets trivial to hook in additional systems.

Quote:>>        also, while we're at it.. can someone pliss tell me about the
>>distance limitations on a Co-ax Segment of a network?  how long cann
>>the total co-ax segment be?
>I think thinnet can go something like 600 feet (~200 meters).

10Base2 (ThinNet) can go 185 meters (606 feet).

Quote:>10baseT can't go that far, I think its max is < 200 feet.

10BaseT can go 100 meters, about 303 feet.

Quote:>                                                           Thin
>coax is a better choice to go a long distance, while Thick coax
>is required to go _really_ far, like between buildings (at least
>if you want to do it without repeaters).

The only acceptable way to go between buildings is with fiber.
10Base5 (Thick Coax) will go 500 meters, but there are grounding
issues to deal with between buildings that are best dealt with
by using fiber.

Gary

--

Disclaimer, datclaimer...
Hestons' First Law: "I qualify virtually everything I say."

Oops; 100 meters is about 328 feet, not 303. Miscalculated
something there....

Gary

--

Disclaimer, datclaimer...
Hestons' First Law: "I qualify virtually everything I say."

Quote:>Hello
>    at work, we have 2 Linux machines hooked together using Coax
>cables and the setup has been working great for the last few months.
>we would like to add a third machine on this lan.  the problem is that
>the third machine is at a distance away from the other 2.  I would
>like to know if ....  it is possible to use Co-ax to hook 2 machines
>together and then... link the third machine using a 10baseT cable from
>it's (third machine's) either Ethernet card.. into the second machines
>SMC Ultra Card.  Will this work?

Nope!

Quote:>    also, while we're at it.. can someone pliss tell me about the
>distance limitations on a Co-ax Segment of a network?  how long cann
>the total co-ax segment be?

As I recall single segment on thin coax can be 300 Meters. There
are a bunch of rules and some extra lengths supportable with
some cards.

Quote:>    and finally, can someone please recommend a good book for
>Network hardware issues?  

>    thanks a lot.

Buy a cheap hub like the SMC Tiger. Comes with a manual that will
explain what you need to know. They come in different configurations
some with 4 or 6 10BaseT ports AND a thin coax port. You can run
you coax from this and plug your hardware additions into the 10BaseT
ports.

Hope this helps.

------------------------------------------------------------------------
Wally Ritchie
Ft. Lauderdale, Florida
------------------------------------------------------------------------

Quote:>  Thinnet Coax cannot have
>tees, Thicknet can; however, I've done it successfully.

"I've done it" falls far short of "it's guaranteed" or even
"it usually works."  Thicknet (10BASE-5 fat yellow cable) doesn't
like branching any better than thinnet (10BASE-2 low-cost coax)
does.  A 1 foot stub will put a big enough ghost on a 10BASE-5
segment to wreck its reliability.  Coax ethernet needs to be
run in a single line with taps along it and terminating resistors
at both ends.  The taps can only be a couple of inches long at
the most, and present only a few picofarads' load, which is why
you can't use a cable between the tee connector and a 10BASE-2 card.

Cameron