1. A system comprising: one or more devices to: receive a word, of a block of words within traffic, on which to perform forward error correction, each word of the block of words including respective encoded bits and respective sets of reliability bits for identifying a respective level of reliability of each one of the respective encoded bits, identify, within the word, least reliable positions that correspond to a subset of encoded bits associated with one or more lowest levels of reliability; generate a set of candidate words based on different combinations in which the subset of encoded bits can be inverted; determine a first quantity of errors associated with a first candidate word of the set of candidate words and a second quantity of errors associated with a second candidate word of the set of candidate words, determine whether the first quantity of errors or the second quantity of errors corresponds to an odd value, invert a parity bit, associated with the second candidate word, when the second quantity of errors corresponds to the odd value, determine, based on inverting the parity bit, whether a first bit or a second bit is inverted, the first bit being most reliable among the subset of encoded bits within the first candidate word, and the second bit being most reliable among the subset of encoded bits within the second candidate word, select the first candidate word when the second bit is inverted, and perform forward error correction on the word, using the first candidate word, based on the selection of the first candidate word.