Triple-Speed Ethernet Intel® FPGA IP User Guide

ID 683402
Date 10/12/2023
Public
Document Table of Contents

A.3. Pause Frame Format

A pause frame is generated by the receiving device to indicate congestion to the emitting device. If flow control is supported, the emitting device should stop sending data upon receiving pause frames.

The length/type field has a fixed value of 0x8808, followed by a 2-octet opcode field of 0x0001. A 2-octet pause quanta is defined in the second and third bytes of the frame payload (P1 and P2). The pause quanta, P1, is the most significant byte. A pause frame has no payload length field, and is always padded with 42 bytes of 0x00.

Figure 92. Pause Frame Format