802.1Qdt – Amendment: PFC Enhancements

The full title of this corrigendum is “Standard for Local and Metropolitan Area Networks–Bridges and Bridged Networks Amendment: Priority-based Flow Control Enhancements “.

The scope of proposed amendment specifies procedures and managed objects for automated Priority-based Flow Control (PFC) headroom calculation and Media Access Control Security (MACsec) protection of PFC frames, using the existing Precision Time Protocol (PTP) and enhancements to the Data Center Bridging Capability Exchange protocol (DCBX).  The proposed amendment places emphasis on the requirements for low latency and lossless transmission in large-scale and geographically dispersed data centers. The proposed amendment also addresses errors of the existing IEEE Std 802.1Q functionality.

PFC is used to avoid packet loss in low latency, high reliability Ethernet data centers and data center interconnects. For PFC to function properly and without wasting memory, the amount of headroom buffer must be calculated. Deployment in large scale data center networks and long distance interconnects is currently problematic and requires manual configuration. There are customer requirements for the integrity and confidentiality protection of all frames transmitted between geographically distributed data centers. The current specification is inconsistent and incomplete regarding the operation of PFC and MACsec together..

Current Status

Status Project approved
Current Draft   
PAR  PAR (Approved: 13 May 2022; Expires: 31 Dec 2026)
Editor  Lily Lv


Date Document


Date Document
10 Jul 2022 PFC Enhancements Discussion – PFC Management 
14 Nov 2021 Recap of Headroom and Enhancements Project Proposal
23 Sep 2021 PFC Headroom and Enhancements Project Proposal
02 Jul 2021 PFC Headroom Measurement and Calculation Project Proposal
21 Jun 2021 Adaptive PFC Headroom and PTP
08 Mar 2021 Adaptive PFC Headroom