5000' Ethernet?

Dean Weimer dweimer at orscheln.com
Thu Jul 16 22:05:12 UTC 2009

>Not directly FreeBSD related, but how much of a chance is there that two
>machines could communicate directly over 5,000 feet of cat5 with no
>special hardware?
>IIRC the classic Ethernet problem limiting the distance between the
>farthest points on a network had to do with timing and collisions. If
>these two NICs are configured full duplex then it seems one would have
>no idea how far away the other was due to timing issues.
>100baseT uses lower power drivers than 10baseT, so perhaps 10baseT would
>work better.

>In any case, have boxes of cat5 on order so as to find out myself.

>Are there any particular range extenders you have used and would
>recommend for making this task a sure thing on the first try? Perhaps I
>should put an inexpensive Ethernet switch at each junction to serve as a
>regenerative repeater?

I must say that all the information about Ethernet you have gotten about this has been quite interesting , but it seems a lot of people forgot that a simple answer is often the best answer.  Basically you don't need to know all the info about timing and how Ethernet handles collisions.  What you do need to know is that many people have research this, and that's why Cat5 cable standard has a maximum length of 100 meters or 328 feet, they have found this to be the maximum length that it reliably works.  In order to go 5000 feet, you would actually need 15 repeaters.  I have never tried to string that many switches or repeaters together though in my experience if you buy this many low end switches you will likely have one bad one in the bunch.  Plus there's a lot of places you would need power, and if this is outside now you have to take the weather into account.
It's unfortunate that wireless was ruled out as this would be the easiest method, and likely the cheapest.  The next option I would look to is definitely fiber as you had mentioned before.  I have only ordered fiber through our installer they come out string it polish and terminate the ends.  Then we just plug in the patch cables.  As for a supplier I checked some of the major vendors we use for cabling, they all offer only patch cables for fiber, my guess is that if you need to buy a spool, it would have to be from a whole sale outfit, and then you would need someone to put the ends on.  Your best bet would be to search for data and communication cable installation services in your area.  I would still quote wireless if it's feasible in the location as your customer (or management if this is for an in house operation) may change their mind after presented with the cost of a temporary fiber installation, and the problems a cat5 run would require overcoming.
Hope this helps some,
     Dean Weimer
     Network Administrator
     Orscheln Management Co
     Phone: (660) 269-3448
     Fax: (660) 269-3950

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