Ethernet Hubs Explained Segment 3 of 3 (Installation Architecture)
Typically, a hub is installed behind a router. Where the router asserts the extra intelligence necessary to imply and manage IP addresses and thereafter, the hub just mindlessly makes that IP information available through its Ethernet interfaces. So if your house or small business already has a properly operating router, you can install a hub to give access to additional Ethernet devices or computers. Or, in a situation like a college dorm room, where the internet service provider has already set up an Ethernet interface with multiple IP addresses and routing, you would simply install a hub to expand the network for additional computers for your roommates inside the dorm.
A hub is also very useful for diagnostic or troubleshooting or monitoring purposes because it essentially creates a passive wire tap. You can connect debug instruments, monitoring equipment, "packet sniffers", or PC equipped tools to analyze the traffic here for troubleshooting and analysis purposes.
Now, on a scale of intelligence for network components, the only thing dumber than a hub is a passive Ethernet wire or cable. And on that same scale of intelligence for network devices the next device more intelligent than a hub is an Ethernet switch.
This is the text from the movie entitled "Ethernet Hubs", published at http://www.askmisterwizard.com/. You can learn more about the video version and purchase an inexpensive personal license to view it by clicking right here. This text also includes a few static images from the movie.