title: What is the relationship of DMA ring buffer and TX/RX ring for a network card?
body: <p>I know that for a network card, OS must allocate tx/rx rings for it so that when OS wants to receive/transmit packets, the network card will know where the packets are and which packets are to be transmit.</p>
  
  <p>And when I read about DMA, I see something named DMA ring buffer. Are the DMA ring and tx/rx ring the same thing?Or what is the relationship?</p>