In this article there is a sentence like this
The groundbreaking fact about channel capacity, though, was not simply that it could be traded for or traded away
The whole circumstance is
Shannon’s paper was the first to define the idea of channel capacity, the number of bits per second that a channel can accurately handle. He proved a precise relationship between a channel’s capacity and two of its other qualities: bandwidth (or the range of frequencies it could accommodate) and its ratio of signal to noise. The groundbreaking fact about channel capacity, though, was not simply that it could be traded for or traded away. It was that there is a hard cap—a “speed limit” in bits per second—on accurate communication in any medium. Past this point, which was soon enough named the Shannon limit, our accuracy breaks down.
I don't really understand the meaning of that sentence. What does it mean by trade away and trade for in that sentence?