Looking for various documents and the IEEE standards, I can see that 802.3bd-2011 adds a MAC control frame for priority-based flow control. How does priority-based flow control differ from IEEE 802.1P/802.1D-2004 (which is now in IEEE 802.1Q-2005).
In IEEE 802.1Q we have PCP values for QoS at layer 2;
Is priority based flow control something different then, to PCP values?
According to Wikipedia, 802.3bd was:
An amendment by the IEEE 802.1 Data Center Bridging Task Group (802.1Qbb) to develop an amendment to IEEE Std 802.3 to add a MAC Control Frame to support IEEE 802.1Qbb Priority based Flow Control.
What was the need for this?
Please provide a/some references for your answer so I can read them.