31.6.3.1 Packet Buffer DMA

  • Easier to guarantee maximum line rate due to the ability to store multiple frames in the packet buffer, where the number of frames is limited by the amount of packet buffer memory and Ethernet frame size
  • Full store and forward, or partial store and forward programmable options (partial store will cater for shorter latency requirements)
  • Support for Transmit TCP/IP checksum offload
  • Support for priority queuing
  • When a collision on the line occurs during transmission, the packet will be automatically replayed directly from the packet buffer memory rather than having to re-fetch through the AXI (full store and forward ONLY)
  • Received erroneous packets are automatically dropped before any of the packet is presented to the AXI (full store and forward ONLY), therefore reducing AXI activity
  • Supports manual RX packet flush capabilities
  • Optional RX packet flush when there is lack of AXI resource