Recommendation ITU-T G.998.4 specifies techniques beyond those defined in the existing ITU-T digital subscriber line (DSL) Recommendations ITU-T G.992.3, ITU-T G.992.5 and ITU T G.993.2 to provide enhanced protection against impulse noise or to increase the efficiency of providing impulse noise protection (INP). This version of this Recommendation integrates all of the previous amendments and corrigenda with the 2015 version 2.0 of Recommendation ITU-T G.998.4. This version of Recommendation ITU-T G.998.4 corrects or adds the following functionality: - Valid values for RS FEC (corrigendum); - Maximum error-free throughput (EFTR_max) (amendment) - Minimum/accumulated/maximum NDR reporting with disabled retransmission (amendment