SMF

3GPP Release 16-Compliant Generic UDM Enhancements

SMF supports the following enhancements in compliance with 3GPP 29.503, Release 16.

• Subscription Level 3GPP Charging Characteristics: When this attribute is available in DNN configuration, this attribute takes precedence over the one received in the SessionManagementSubscriptionData.

• ePDG Indication and NF Registration Time: UDM message handling configuration includes additional keyword options to allow or ignore ePDG Indication access information and NF Registration time in the N10 Registration Request.

Default Setting: Not Applicable

CHF Failure Handling at Rating Group and Application level

SMF allows you to define configurable actions to handle the failures associated with the application errors and rating group IDs.

This feature introduces new command failure-handling error-type [ rg | app ] in the charging profile configuration. For more information, see the profile charging failure-handling error-type command.

Default Setting: Disabled - Configuration Required

Dual Stack Support on N3

SMF enables the dual stack transport for N3 tunnel using the dual-stack-transport { false | true } CLI command in UPF network profile.

Default Setting: Disabled – Configuration Required

EPS Fallback Reporting

SMF supports EPS Fallback Reporting functionality for PCC rules for which the EPS_FALLBACK trigger was sent by the PCF.

Default Setting: Enabled when the compliance version 16.10.0 is set for npcf-smpolicycontrol.

Handle TFT Changes in the Absence of refQosData

SMF handles the PCC rule modification, with the following IEs as optional in smPolicyDecision.

• refQosData in PCC Rule

• refChgData in PCC Rule

• flowInfos in PCC Rule

• qosDesc in smPolicyDecision

• chgDecs in smPolicyDecision

• pccRules in smPolicyDecision

All the valid use cases work as expected even if these optional IEs are not received.

N3IWF for Untrusted Non-3GPP Access Network

SMF supports the N3IWF interface for interworking between 5G core and untrusted non-3GPP networks.

N3IWF facilitates seamless handover and uninterrupted connectivity for users when they transition between different network types.

Default Setting: Disabled – Configuration Required

cnPGW-C

Debuggability and Logging Enhancements

For IoTaaS solutions, SMF supports the following enhancements:

• Update statistics related to RADIUS, Diameter, PCC rules, and APN

• Improve transaction and application level logs

• Update Event trace

• Improve monitor subscriber display

For more information on the statistics, see the UCC 5G SMF Metrics Reference for the applicable release.

Default Setting: Not Applicable

3GPP-Negotiated-DSCP Attribute Information

Previous Behavior: SMF used to send incorrect value of 3GPP-Negotiated-DSCP attribute in the RADIUS authentication and accounting request messages.

New Behavior: For 3GPP RADIUS dictionary, SMF populates RADIUS authentication and accounting messages with the correct value of 3GPP-Negotiated-DSCP attribute.

For RADIUS authentication, SMF uses the QCI and ARP information from Create Session Request and detects an exact match in the QoS profile configuration. If not found, SMF checks for a match with only QCI and proceeds to populate the 3GPP-Negotiated-DSCP attribute value. The processing remains the same for RADIUS accounting except that SMF uses Gx authorized QCI for match finding.

Conditional Presence of IMSI IE in Change Notification Response

Previous Behavior: When a Change Notification Request is received with the IMSI Information Element (IE), the IMSI IE is not included in the corresponding response message.

New Behavior:If the IMSI is received in the Change Notification Request, SMF includes the conditional IMSI IE in the Change Notification Response message, in compliance with 3GPP 29.274, Release 16. In the case of emergency sessions where IMSI is absent, the IMEI gets included in the Change Notification Response if it was received in the corresponding Change Notification Request.

Initiation of PDU Modification on Policy Update

Previous Behavior: SMF did not take any action for changes to the Session-AMBR and QoS parameters in the Policy Update Response message.

New Behavior: SMF initiates the PDU modification procedure if the Session-AMBR and QoS parameters are received in the Policy Update Response message.

Outer Header Removal IE Value During Upgrade or Activation of Dual Stack

Previous Behavior: SMF used to read the configured dual stack value and send the configured value to the UPF for all N4 messages.

New Behavior: SMF saves the configured dual stack value during the session establishment.

SMF uses the same dual stack value in the subsequent N4 messages until the session gets disconnected.

Processing URR During Gy CCA-I Failure

Previous Behavior: SMF disabled the charging for the session if the corresponding FHT action was set to CONTINUE and Sub action as NONE/UNKNOWN in Gy CCA-I.

There was no communication towards OCS after Gy CCA-I for the mentioned FHT action and sub action.

New Behavior: SMF sends Create/Update URR with high quota when the Gy CCA-I failure occurs and the FHT action for the session is set to CONTINUE and Sub action as NONE/UNKNOWN. SMF continues to stop further communication of Gy CCR-U/T towards the OCS.

Validation of Subnet Address in IPAM Configuration

Previous Behavior: While defining the chunk-group size, the CLI address-range allows configuring odd subnet address-range. It causes uneven or incorrect distribution of chunks across the DPs.

New Behavior: The CLI address-range allows to configure only even subnet address-ranges. When chunk-group is enabled, the number of IPs in the address range should be a power of 2, which implies, the number of IPs should be even. If the address range has odd number of IPs, the following error message appears:

"address range from " + startAddr +" to "+ endAddr + " is odd"