ETSI TS 186 008-4 contains the performance benchmark requirements applicable to IMS/PES/VoLTE exchange
implementations based on Recommendation ITU-T Q.543 [1] and ETSI TS 101 563 [10].The definitions of IMS/PES/VoLTE design objectives are based on "best practice" performance of legacy PSTN/ISDN
signalling. The values contained in the present document are "best practice" performance values measured on IMS and
PES implementations. The ISDN VGW values are based on carrier grade implementations.