Q23: Problems arising when using crossover cables

The normal way to connect computers in a 10Base-T or 100Base-TX LAN is to use an Ethernet hub or switch. When a NIC receives the link pulses coming from the hub, it lights the green LED and tells the system the connection is on.

However, it is possible to create a simple two-node Ethernet network without using a hub by connecting the NIC of two computers directly, using what is known as a crossover cable. As long as the two computers are powered on, each NIC receives link pulses from the other and everything is OK.

The problem arises when one of the two machines is powered off. The remaining NIC does not see anymore incoming pulses and send a "broken link" signal to the system. Is this case Windows 2000 and Windows XP use to disable the TCP/IP and WOOWEB/WOOWEB-PRO cannot work any longer.

To sum up, when using WOOWEB/WOOWEB_PRO to share the Internet connection between two computers that are interconnected with a simple crossover cable, the two computers must stay powered on. The server itself cannot acces the Internet when the client is powered off.

This condition is rather constraining. In other words, the children computer must be powered on to allow the parents to access the internet! The solution consists in using a hub or a switch even for two computers.

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