"This Recommendation contains the benchmark testing of signalling parameters against the performance design objectives specified in ITU-T Q.543 and ETSI TS 101 563@ which are applicable to IMS/PES/NGN and VoLTE implementations. The values of the performance design objectives (reference load A and reference load B)@ which are contained in this Recommendation and found in Table 1 to Table 9@ are taken from ETSI TS 101 563. These values are ""best practice"" performance values measured on IMS/PES/NGN and VoLTE implementations. "