When I first got into networking I thought that to connect to Ethernet machines you had to plug them into a hub or a switch. It turns out there is a much cheaper way to do this if you are only connecting two machines.
But what if you don’t want to pay for a hub or a switch. After all you’ve only got two machines. Well, under normal conditions if you wire two ethernet cards directly into one another, they will not understand how to talk to each other. A cross-over-cable takes care of this. It swaps the position of a couple of wires in the plug from end to the other so that each end of the connection sees the correct wires from its perspective.
Using this what you can do then is get two network cards for $20 each (Less if you are brave) and connect them with a cross-over-cable. Thats all it takes. Using a switch you would need the two network cards, a $50 switch, and two normal cables to connect everything.
What’s even cooler is that the cross over cable is the fastest possible ethernet connection. Switches have buffers, hubs have collissions, cross-over-cables don’t have either. They transmit immediately and correctly every time.
Finally, if you want to connect a cable modem to this two machine network you might think you have to invest in a cable router. While they are terrifically handy devices, you don’t absolutely have to get one. You can add a second ethernet adapter to one machine and set it up as a simple a firewall/router. (That however is beyond the scope of this article.) The advantage of this setup is the 2nd NIC costs about half what a cable router would cost.