5000' ethernet?

Olivier Nicole on at cs.ait.ac.th
Thu Jul 16 02:25:10 UTC 2009


A general reply to many suggestions.

> So the time it takes for the smallest Ethernet frame to get from the two 
> farthest nodes will determine a window in which the two most distant nodes 
> upon attempting a transmit can tell that a collision occurred and 
> retransmit.

In a case of point-to-point UTP cable, there would be no collision
though. But acknowledgement packets may take too long to reach the
sending end, leading it to beleive the packet was lost and needs
retransmission. I cannot rememebr if Ethernet have ACK packets.

> The max distance for UTP is 328 ft. Divide the 5,000 by 328 and it will tell 
> you how many bridges, hubs, or switches you will need to regenerate the 
> signal. You may find devices purporting to 'range extenders', but even these 
> will have distance limitations requiring more than one. Foofaraw.

That would make 14 hub/switches. I think I remember that the number of
hubs is limited to 4 in between each end of the connection. I am not
sure it is true also for switches.

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

You would need 5 boxes, the connections between each run of cable
could cause too many loss, even if the timing was not an issue.

As suggested by others, I would go for wireless ad it is the easiers
to install if you have a line of sight. A complete wireless solution
would range as little as $1500 including a couple of parabolic
antennas with 18-20dB gain and the access point including power over
Ethernet to power the antenna.

Another solution, if you really don't need that much bandwidth, is to
request an ADSL connection at each location and establish some kind of
tunnel in-between the two boxes. For you this solution is zero cable
installation, and very light configuration (ethernet over IP tunneling
would allow you to extend your Ethernet layer 2 network across both
end of the link). Of course you will be limited to the downlink
bandwidth of your ADSL connection: if you get 20Mbps ADSL (that is
20Mpbs uplink/10Mbps down), you would have 10Mbps link. This solution
should be quite cheap depending on your contract with your telephone

As suggested before you could consider fiber optic, you could order
a 2000 meters roll of underground outdoor fiber, with pig tail
installed at each end. For a temporary use, you should not need any
special precaution for installation: these fibers are usually shielded
to support a truck to running on it... Or you can get the type of
fiber designed for aerial usage, 8 shapped cable, including a
suspension cable, and run it from tree to tree; but it's much much
more installtion work, the cable tend to be heaviy...

And you could get a couple of media converters (UTP to fiber) for
$1000. Don't be afraid by the cost of fiber optic, most of the cost is
labour to bury the fiber, it is not the cost of the cable
itself. AFAIR, you can run 100Mbps on 2 kilometers of multimode fiber
(multimode is cheaper I beleive).

My choice would be:

If I have the line of sight and the budget, I would go wireless,
second choice being ADSL and third fiber optic.



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