 Scope One of the ISSI Measurement Methods for Voice Services provides detailed measurement procedures to measure the ISSI Voice Service (IVS) Call Set-Up Delay (CSD) and IVS Message Transfer Delay (MTD) performance for SU-to-SU and Group calls.IVS-CSD and IVS-MTD performance parameters are used to evaluate the delay associated with successful packet transfers across RFSSs and across the IP backbone connections that link adjacent RFSSs.The ISSI Performance Recommendations for Voice Services is a companion standard to the ISSI Measurement Methods for Voice Services standard.