Section: D.4.3.1.1 Charging Trigger Function
Content: For a service utilizing the distributed CTF, the CTF is divided into two functional blocks as described in clause 4.3.1.1. The Accounting Metrics Collection (AMC) function block is in the UE that supports the specific service. The AMC sends usage information collected to the Accounting Data Forwarding (ADF) function block of the CTF in the service NE over the service-specific reference point, denoted as X. The subset of X specific to usage information collection for charging purposes is denoted as Xch in figure D.3.2.1.