Frame check sequence

Frames are used to send payload data from a source to a destination.

All frames and the bits, bytes, and fields contained within them, are susceptible to errors from a variety of sources.

The FCS field contains a number that is calculated by the source node based on the data in the frame.

When the destination node receives the frame the FCS number is recalculated and compared with the FCS number included in the frame.

[2] The FCS is often transmitted in such a way that the receiver can compute a running sum over the entire frame, together with the trailing FCS, expecting to see a fixed result (such as zero) when it is correct.

Structure of an Ethernet packet, including the FCS that terminates the Ethernet frame ^{[

1

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