This Supplement provides guidelines on the quality aspects of protocol related ITU-T Recommendation with the objective of:1) improving the quality of protocol related Recommendations;and 2) helping to improve the interoperability of products based on these Recommendations.In order to encourage the widest possible use of ITU-T Protocol Related Recommendations,it is important that these Recommendations are of the highest possible quality.Several aspects of Quality that play an important role for users of these ITU-T Recommendations have been selected for this purpose.These are:readability,completeness,correctness,consistency, unambiguity,implementability and testability.