25G Ethernet Intel® Stratix® 10 FPGA IP User Guide

ID 683154
Date 9/15/2021
Public

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4.1.4.2. IP Core Malformed Packet Handling

While receiving an incoming packet from the Ethernet link, the 25G Ethernet Intel FPGA IP core expects to detect a terminate character at the end of the packet. When it detects an expected terminate character, the IP core generates an EOP on the client interface. However, sometimes the IP core detects an unexpected control character when it expects a terminate character.

If the 25G Ethernet Intel FPGA IP core detects an Error character, a Start character, an IDLE character, or any other non-terminate control character, when it expects a terminate character, it performs the following actions:

  • Generates an EOP.
  • Asserts a malformed packet error (l1_rx_error[0] ).
  • Asserts an FCS error (l1_rx_error[1] ).

If the IP core subsequently detects a terminate character, it does not generate another EOP indication.

When the IP core receives a packet that contains an error deliberately introduced on the Ethernet link using the 25G Ethernet Intel FPGA IP TX error insertion feature, the IP core identifies it as a malformed packet.

At this time, the 25G Ethernet Intel FPGA IP core does not recognize non-zero 4-bit ordered set types as an error.