Low Latency Ethernet 10G MAC Intel® FPGA IP User Guide

ID 683426
Date 3/01/2022
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4.5.6. CRC and Padding Bytes Removal

By default, the MAC RX forwards receive frames to the client without removing the CRC field and padding bytes from the frames. You can configure the MAC RX to remove the CRC field by setting the rx_padcrc_control register to 1. To remove both the CRC field and padding bytes, set the rx_padcrc_control register to 3.

When enabled, the MAC RX removes padding bytes from receive frames whose payload length is less than the following values for the different frame types:

  • 46 bytes for basic frames
  • 42 bytes for VLAN tagged frames
  • 38 bytes for stacked VLAN tagged frames

The MAC RX removes padding bytes only when the VLAN and stacked VLAN detection is enabled (rx_vlan_detection[0] = 0). Otherwise, the MAC RX does not remove padding bytes even if padding bytes removal is enabled.