What is the purpose of the forward error correction (FEC) interleaving layer?

The purpose of the forward error correction (FEC) interleaving layer is primarily to reduce the probability of an impairment event corrupting more than one bit in a string. This technique rearranges the data bits in a way that spreads them out across a larger range, effectively breaking up the sequences of bits. When errors occur due to noise or interference, they are more likely to affect consecutive bits in a stream.

By interleaving the data, if an error occurs during transmission, it will impact bits that are distributed across the data stream rather than affecting a block of consecutive bits. This allows the FEC mechanisms to recover more easily from errors, as the spread nature of the bits provides more options for error correction. Thus, interleaving plays a crucial role in ensuring data integrity by enhancing the resilience of transmitted data against burst errors.

The other options pertain to different aspects of data transmission but do not accurately capture the specific function of FEC interleaving in reducing the impact of error events on data integrity.