In the B2B scenario, the charging architecture may involve three modes of interaction:

• B-CHF only interaction: the NF (CTF) collects and reports the charging information per business, alternatively it collects and reports the charging information per consumer but for business charging purposes, to the business CHF (i.e. B-CHF).
• B-CHF via C-CHF interaction: the NF (CTF) collects and reports the charging information per consumer to a consumer CHF (i.e. C-CHF), and the C-CHF reports the charging information per consumer to the business CHF (i.e. B-CHF).
• C-CHF via B-CHF interaction: the NF (CTF) collects and reports the charging information per consumer to a business CHF (i.e. B-CHF), and the B-CHF reports the charging information per consumer to the consumer CHF (i.e. C-CHF).

In the B2B charging architecture with B-CHF only interaction, the charging information collected by the NF (CTF) is per business or per consumer but used for business charging purpose. When B-CHF or C-CHF may be applicable, is specified in the middle tier charging TSs. The B-CHF performs charging functionalities for the business. The related NF(s) and the corresponding references for B2B charging with B-CHF only, but not limited to:

• Network exposure domain charging: NEF charging per API invocation/notification, as specified in TS 32.254.
• Edge charging: CEF based charging and EAS deployment charging, as specified in TS 32.257.
• Short message charging: SMSF charging for IoT, as specified in TS 32.274, in this case the charging information is collected per consumer but is applicable to business context.
• Prose charging: ProSe Function or DDNMF for prose discovery and prose communication charging, as specified in TS 32.277, in this case the charging information is collected per consumer but is applicable to business context.
• 5G LAN charging: NEF charging/CEF based charging for 5G VN group management, as specified in TS 32.254.
• NPN charging: SMF and AMF charging for the inter-provider charging of NPN, as specified in TS 32.255 and TS 32.256, in this case the charging information is collected per consumer but is applicable tobusiness context.
• Network slice charging: NSPA, NSM and NSACF charging per S-NSSAI for network slice, specified in TS 28.201, TS 28.202 and TS 28.203.
• TSN charging: TSN AF charging for TSN Bridge management and configuration, NEF and TSCTSF charging for the enabler of TSC and TS, specified in TS 32.282.

In the B2B charging architecture where the NF (CTF) have direct C-CHF interaction and where the C-CHF interact with the B-CHF using N108 reference point, the charging information collected by the NF (CTF) is per consumer. The C-CHF performs charging functionalities for the consumer. The B-CHF performs charging functionalities for the business. The related NF(s) and the corresponding references for the B2B charging with business CHF via consumer CHF include, but not limited to:

• Network slice charging: inter CHF interaction to support converged charging for tenant and UEs belonging to the tenant at same time, as specified in Figure 4.3-1 of TS 32.255.
• TSN charging: inter CHF interaction to support converged charging for TSC traffic belonging to the same TSN bridge, as specified in Figure 4.3-1 of TS 32.255.

In the B2B charging architecture where the NF (CTF) have direct B-CHF interaction and where the B-CHF interact with the C-CHF using N107 reference point, the charging information collected by the NF (CTF) is per consumer and used for both B2C and B2B charging. The related NF(s) and the corresponding references for the B2B charging with B-CHF, where the B-CHF interacts with the C-CHF include, but not limited to:

• 5G data connectivity charging in local breakout roaming scenario, as specified in Figure 4.2.6a of TS 32.255;
• 5G connection and mobility charging, in local breakout roaming scenario, as specified in Figure 4.2.2.3 of TS 32.256;

The following sub-clauses detail the charging principles on the basis of the B2B converged charging architecture, in respect of:

• B2B charging information utilisation
• B2B charging data generation and quota supervision
• B2B charging data transfer

In the B-CHF only interaction, the NF (CTF) collect and report the charging information per business subscriber to B-CHF. In the B-CHF via C-CHF interaction, the NF (CTF) collect and report the charging information to C-CHF. C-CHF report the charging information per business subscriber to B-CHF. In the C-CHF via B-CHF interaction, the NF (CTF) collect and report the charging information to B-CHF. B-CHF report the charging information to C-CHF. The identification for the business subscriber is specified in the respective middle tier TS, e.g.

• Tenant Identifier in TS 28.201, TS 32.282.
• EAS Provider Identifier in TS 32.257.

Both B-CHF and C-CHF can generate CDRs, with information for both individual subscriber identification and the related business subscriber identifications if any.

• The B-CHF generate CDRs for the business subscriber.
• The C-CHF generate CDRs for the individual subscriber.

In the B-CHF only interaction, the quota is requested and granted between CTF and B-CHF.

• The CTF request and consume quota from B-CHF.
• B-CHF grant quota to the CTF.

In the B-CHF via C-CHF interaction, the quota is requested and granted between CTF and B-CHF via C-CHF.

• The CTF request and consume quota from B-CHF via C-CHF.
• B-CHF grant quota to the CTF.
• C-CHF forward and re-allocate quota.

The Nchf services for interaction between C-CHF and B-CHF are specified in TS 32.290.

In converged charging, charging events mirroring the resource usage request of the user are transferred from the CTF, CEF or CHF to the CHF via the Nchf service-based interface, specified in the respective middle tier TS.