SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
Protocol errors occur when the port logic detects that the received packet did not pass protocol specific criteria that was checked during reception of the packet. Examples of protocol errors include packet length errors, CRC errors, or alignment errors.
When protocol errors are detected, the port may choose whether or not it will drop the packet. The mechanism that is used to determine which packets to drop and which to forward is application specific. If the port determines that it needs to forward the packet to the Host, it will set the Packet Error bit in the Descriptor indicating that this is a packet which experienced a protocol related error. The type of protocol related error is generally indicated in either the Protocol Specific bits in the Host or Monolithic descriptor or in the Protocol Specific bytes region. The packet length information and certain portions of the Protocol Specific region may not be correct for packets which encounter errors.