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.
Hubs: As you can see in the image an ethernet hub transmits the data frame to every device, except the device that sent the frame. A hub is just a pass-through and distribution point for every device connected to it, without regard of what kind of data is passing through and where the data might be going. Today, hubs are outdated technology that have been replaced by switches.