You Can't Lease the Cross-Over Cable, So Lease
Something Almost Just Like It
We've established the fact that you can't buy or lease an
actual Ethernet cross-over cable from the telco. But what if the telco would
lease to you something like the following?
Use a service between two routers that acts like a cable with
four wires (two pairs) in it.
When a router sends on one pair, that pair is crossed to the
other pair before it gets to the other end cable. That way, when one router
sends on one pair, the other router receives on the other pair.
Because the service requires that you physically encode data a
little differently than on Ethernet, your routers have to use a different type
of interface, called a serial interface.
The end result will be that two routers can send and receive
data to and from each other.
Well, the end result is that the routers can forward packets to
each other, and that's exactly what the telco offers. The telco essentially can
lease you a 4-wire cable, or 4-wire circuit, between two
points. Although it's not exactly Ethernet, it sure acts a lot like an Ethernet
The telcos have been well prepared to offer 4-wire circuits to
their customers for decades. They have already run cables between almost every
town and city. They have offices, called central offices
(COs), almost everywhere as well. In addition, telcos have the right-of-way, which is the legal
right to dig up roads and put cabling in the ground and overhead, all for the
common good of the populace. In effect, the telco can run the cable for you to
create this 4-wire circuit.