A "router" is a network device that forwards or "routes" TCP/IP data between
your network and the Internet. Routers are typically separate boxes that
connect to your network and the Internet. However, Windows 98 S/E (and higher)
provides a feature called "Internet Connection Sharing" ("ICS") which lets a
PC connected to the Internet act as a simple router and DHCP server. 

On the Internet side of a router, all of the TCP/IP data seems to be going to 
a single IP address, while on the network side, the router distributes the 
data to each node on the network, each with a distinct IP address.

Using ICS on a PC can be a daunting task because if something goes wrong,
there is little user interface to help you troubleshoot. Also, if the ICS PC
host crashes, every PC and AudioTron on the network will lose its Internet
connection. 

Sharing a cable or DSL modem on an ICS host PC will also require two 
Ethernet adapters in the PC, and figuring out which one is connected 
can be complicated. For this reason, it's much easier to set up a separate 
hardware router on your network.

_____________________________________________________________________________