Typically, the tied product may be a less desirable one that the buyer might not purchase unless required to do so, or may prefer to get from a different seller. If the seller offering the tied products has sufficient market power in the tying product, these arrangements can violate the antitrust laws.
In general, a hub refers to a hardware device that enables multiple devices or connections to be connected to a computer. An example is a USB hub, which allows multiple USB devices to be connected to one computer, even though that computer may only have a few USB connections. The picture to the right is an example of a USB hub. Note: In the Device Manager, the root hub is your computer and the first USB hub.
We'll start with the simplest device, the Hub. A hub is a repeater, which is a OSI model device, the simplest possible. A hub takes the data that comes into a port and sends it out all the other ports in the hub. It doesn't perform any filtering or redirection of data.