Compounds. There are more carbon compounds than there are compounds of all other elements combined. The study of carbon compounds, both natural and synthetic, is called organic chemistry. Plastics, foods, textiles, and many other common substances contain carbon.
backplane is the shared capacity between interfaces on a switch switch fabric is also the shared capacity between interfaces on a switch and can also be the shared capacity between interfaces on multiple switches using some sort of interconnect, typically vendor specific.
Learning in a backpropagation network is in two steps. First each pattern Ip is presented to the network and propagated forward to the output. Second, a method called gradient descent is used to minimize the total error on the patterns in the training set.