The DCMAC Subsystem provides a comprehensive mechanism for pause packet termination and
generation in Coupled MAC+PHY mode exclusively. The TX and RX have independent
interfaces for processing pause information as described in this section. The subsystem
is capable of handling 802.3x and priority-based pause operation. The RX path parses
pause packets and presents the extracted quanta on the
rx_pause_quanta{0..8} buses. The TX path can accept pause packet
requests from the pause interface and inject the requested packets into the data stream.
Both global pause packets and priority-based pause packets are handled. Note: 802.3x and global pause are used interchangeably throughout
the document.