PFC Frame

Introduction PFC (Priority-based Flow Control) function in Ethernet.

The Priority-based Flow Control (PFC) operation is used to inhibit transmission of data frames on one or more priorities for a specified period of time. The behavior of a MAC Control client supporting PFC operation is specified in IEEE Std 802.1Q.

MA_CONTROL.request primitive

The globally assigned 48-bit multicast address 01-80-C2-00-00-01.
The PFC opcode 16'h01-01.
A request_operand list with two operands: priority_enable_vector and time_vector.

The PAUSE operation cannot be used to inhibit transmission of MAC Control frames.
When MAC Control PFC operation has been enabled, MAC Control PAUSE operation shall be disabled.
PFC is intended for use over full-duplex point-to-point links. It is not intended for EPON.

Frame format

Please refer to MAC control frame format.

Reference

802.3-2022 Annex 31D - MAC Control PFC operation