To configure the RAT type with the local authorization under the DNN profile, use the following sample configuration:

config 
   profile dnn dnn_profile 
      authorization local rat-type [ nr | eutra | wlan ] 
      end 

NOTES:

• authorization local : This command skips the SDM messages for EPS sessions only. Upon configuring this command under the selected DNN profile, the SMF skips the UDM interaction for fetch subscription. The SMF uses the values received in the Create Session Request message. The SMF skips the UDM interaction to receive ‘Subscribe-for-Notifications’ from the UDM.

• rat-type [ nr | eutra | wlan ] : This keyword skips the following SDM messages based on the specified RAT type.

  • udm subscription-fetch

  • subscribe-to-notifications

  • unsubscribe-to-notifications

  Upon configuring the RAT type with authorization local command in the selected DNN profile, then for sessions on that RAT-type, the SMF skips the UDM interaction for the following messages:

  • udm subscription-fetch during session establishment

  • subscribe-for-notifications during session establishment

  • unsubscribe-for-notifications during session release

• no authorization local rat-type [ nr | eutra | wlan ] : Disables the local authorization under the DNN profile.

The SMF uses both subscription type data from UDM response and the session type configuration in DNN profile to allow or reject the call. The SMF selects the session type based on the initial look up of UE-requested PDN type in the UDM subscription data. Then, the SMF provisions session type for the session based on the selected session type and the session type configured in the DNN profile.

To configure the PDU session type in DNN profile, use the following sample configuration.

config 
   profile dnn dnnprofile 
      session type { IPV4 | IPV4V6 | IPV6 } allowed [ IPV4 | IPV4V6 | IPV6 ] 
      end 

NOTES:

• session type { IPV4 | IPV4V6 | IPV6 } allowed [ IPV4 | IPV4V6 | IPV6 ] : Specify the IP type for the PDU session. The allowed keyword allows you to specify two IP types other than the default session type.

• The SMF uses this session type configuration to process the call. For example, if the UE requested type is IPv4 and the UDM subscription type is IPv4v6, the SMF selects IPv4 in the first pass and subsequently checks against the session type configuration. If the configured session type is IPv6, then the SMF rejects the call with a cause "#51 - PDU session type IPv6 only= IPV4 allowed".

• If the IPAM configuration includes the IP address pool that is different from the finally selected PDU session type, the SMF rejects the call with a cause "#31 - request rejected, unspecified". For example, this cause value will be generated under the following conditions:

  • UeReq-PdnType = V4

  • UdmSubscription-PdnType = V4V6

  • SessionType-Config = V4V6

  • IP-Pool = V6

The Unified Data Management (UDM) is responsible for primarily storing the subscriber data, which SMF accesses for managing the user sessions on the network. The SMF explicitly subscribes to receive the notifications about the events that occur in the subscriber data such session terminate. When the SMF wants to stop receiving the notifications, it initiates the Unsubscribe-to-Notification messages to UDM. Upon receiving these messages, the UDM cancels the subscription by removing the notification subscription for the subscribed session.

Note	The SMF does not receive notification when the UDM-triggered subscription change is observed. However, for UDM-triggered session terminations, the SMF receives notifications from UDM.

This section provides a overview of how the SMF and UDM communicate over the Unsubscribe-to-Notifications message:

1. The NF, such as SMF, sends an Unsubscribe-to-Notifications request to the resource identified by the URI to the UDM. The SMF transacts the request to the UDM over the N10 interface. The Unsubscribe-to-Notifications request allows the SMF unsubscribe from notifications for a specific subscriber session. The SMF receives the URI details during the subscription creation process.

   The Unsubscribe-to-Notifications request contains the ‘SUPI’ and ‘subscriptionId’ in the URI.

2. The UDM processes the request, and based on the response; it sends a response code to the SMF. For example, if the unsubscription is successful, then UDM sends 204 code. If the request is not processed, then the appropriate HTTP status code indicating the error is returned in the response body along with the additional error information.

3. The SMF handles the timeout and failure that occurs when sending the Unsubscribe-to-Notifications messages to the UDM. In case the Unsubscribe-to-Notifications request fails, the SMF continues to purge the corresponding sessions.

   The Unsubscribe-to-Notification message is required for sessions that are hosted on the EUTRA network. Being on this network may not be a requirement for sessions that are released on the NR and WLAN network. For these access types, the SMF sends the UDM registration and deregistration messages that include subscription to notifications through implicit-unsubscribe during the deregistration.

This section describes operations, administration, and maintenance information for this feature.