~~NOTOC~~
====== PFC Frame ======

{{template>:meta:template:pageinfo#tpl
|desc=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.

<callout type="warning" icon="fa fa-exclamation">
  * 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.
</callout>

==== Frame format ====

Please refer to [[network:ethernet:macctrl:start|MAC control frame format]].

==== Reference ====

  * **802.3-2022 **//Annex 31D - MAC Control PFC operation//