Content for TS 23.548 Word version: 19.1.0

1… 4… 4.3 5… 6… 6.2.2.3… 6.2.3… 6.2.3.2.3… 6.2.3.2.5… 6.2.3.3… 6.3… 6.4… 6.5… 6.6 6.7… 6.7.2.4… 6.7.2.6… 6.7.3… 6.8… 6.10… 7… A B… F…

6.8 Support for mapping between EAS address Information and DNAI 6.8.1 General 6.8.2 AF request for DNAI Procedures 6.9 Use of N6 Delay Measurement
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6.8 Support for mapping between EAS address Information and DNAI |R18| p. 74

6.8.1 General p. 74

In order to make sure the AF can query for DNAIs, the 5GS may help determine proper DNAI(s) and notify the information to AF based on AF request providing EAS address information (i.e. IP address(es), EAS IP range(s) or FQDN(s)).

NEF/UDR is configured by OAM with the mapping information between EAS IP address information and DNAI. AF may subscribe the mapping information modification to NEF. AF may request immediate reporting. When the configuration information (relationship between DNAI and EAS address information) is changed, the UDR can notify the new mapping information to NEF. When the mapping information is stored in UDR, NEF may subscribe to mapping information in UDR, where NEF may request immediate reporting. If subscribed to information change, the UDR notifies the NEF with all the corresponding mapping information it has stored for the relevant DNN and/or S-NSSAI, and the NEF notifies the AF.

The EAS address and DNAI Mapping Information record in UDR is shown Table 6.8.1-1. The information elements for the NEF service Nnef_DNAIMapping_Subscribe is specified in clause 5.2.6.8 of TS 23.502.

Table 6.8.1-1: Description of EAS address and DNAI Mapping Information

Parameters	Description
EAS address information	IP address(es) of the EASs or the IP address ranges (IPv4 subnetwork(s) and/or IPv6 prefix(es)) or FQDN(s) where the EAS is deployed for each DNAI. [Mandatory]
DNAI(s)	DNAI(s) for the EAS Deployment information. [Mandatory]
DNN	DNN for the EAS Deployment Information. [Conditional] (NOTE 1)
S-NSSAI	S-NSSAI for the EAS Deployment Information. [Conditional] (NOTE 1)
NOTE 1: At least one of DNN or S-NSSAI shall be present.

6.8.2 AF request for DNAI Procedures p. 75

Reproduction of 3GPP TS 23.548, Fig. 6.8.2-1: AF request for DNAI based on AF request

Figure 6.8.2-1: AF request for DNAI based on AF request

Step 1.

AF invokes Nnef_DNAIMapping_Subscribe service to request the DNAI information. The request includes EAS address information and optionally: DNN, S-NSSAI and AF Identifier.

If mapping information is stored in NEF, skip step 2-3.

Step 2.

If the mapping information is stored in UDR, the NEF determines the DNN and/or the S-NSSAI if not received from the AF, potentially using the AF identifier. If the NEF has not yet received the DNAI mapping information for this DNN and/or S-NSSAI, NEF invokes the Nudr_DM_Subscribe service to subscribe to DNAI mapping information for this DNN and/or S-NSSAI.

Step 3.

UDR notifies the NEF with all the DNAI mapping information for the requested DNN/S-NSSAI.

Step 4.

NEF determines the suitable DNAI(s) using the DNAI mapping information.

Step 5.

NEF notifies the DNAI(s) or the updated DNAI information to AF corresponding to the request in step 1.

If DNAI information is stored in the UDR, whenever the DNAI mapping information change, steps 3 to 5 take place.

6.9 Use of N6 Delay Measurement |R19| p. 75

To enhance EAS and local UPF (re)selection by considering N6 delay measurements per pair of 5GC N6 termination point (i.e. UPF/L-PSA) and the measurement endpoint at application side, as described in clause 4.3.3 of TS 23.502.

The N6 delay measurement results received from the UPF may be used by the SMF in the following way:

The SMF may update the DNS message handling rule on EASDF, e.g. update the EDNS Client Subnet (ECS) option or replace Local DNS Server to be used for a given FQDN.
For an already established connection to an EAS, the SMF may perform L-PSA UPF re-selection and/or an edge relocation considering N6 delay measurement and user plane latency requirement (clause 6.3.6) and then it may also trigger an EAS re-discovery procedure (clause 6.2.3.3).