Section: 5.5.3.11 Charging principles for network slice differentiation in 5G roaming
Content: In the 5G System, the Network Slice is identified by an S-NSSAI (Single Network Slice Selection Assistance Information) within a PLMN, and charging principles for roaming are based on clause 5.15.6 of TS 23.501[ System architecture for the 5G System (5GS) ]  [215]. The HPLMN shall be able to collect charging information in 5G data connectivity and 5G connection and mobility for the home subscribers while roaming, with associated used HPLMN S-NSSAI(s) for retail charging. The VPLMN shall be able to collect charging information in 5G data connectivity and 5G connection and mobility for in-bound roamers, with associated VPLMN S-NSSAI(s) and, in addition, the mapping to HPLMN S-NSSAI(s), for the purpose of wholesale towards the HPLMN. These principles are applicable in both Roaming Home Routed and Local Breakout scenarios.