Search code examples
network-programmingethernetcrc

What if CRC bits have error in Ethernet Frame?


The Ethernet Frame consists of 32 CRC (Cyclic Redunancy Check) bits for checking errors. Won't there be a huge problem if the CRC bits themselves are changed but the message/payload is correct?
Is there a way to detect, avoid and correct this?


Solution

  • No matter crc itself is good or bad, as long as it doesn't match/verify payload (even the payload is still good), this ethernet frame is considered as having a crc error and should be dropped at layer2.

    From what I know, in general we don't do any error "correction" with ethernet. Besides, crc is for error detection, not correction.

    However, mainly upper layer protocol (say TCP) is responsible for reliable delivery and does what it should do to retransmit.