Feature Description

The multi-DNN support enables the SMF to have multiple PDN connections for end users to provide different services including Internet and VoNR services.

The SMF fetches the locally configured profile-based DNN in PDU Session Establishment Request from the AMF. Then, the SMF maintains the PDN connections based on using SUPI and PDU Session ID. The SMF includes the received DNN in all SBI interfaces to authorize the end user to fetch subscription information, policy, and charging related information. The SMF provisions the forward path information to the UPF. The SMF integrates the multi-DNN support with the IP Address Management (IPAM) module to allocate address to the end-user based on received DNN. The SMF maps the DNN-profile that is derived from subscriber policies. The SMF also fetches DNN and IPv4 and IPv6 path information based on IPAM pool configuration and updates the UPF as part of node association interactions.

Note

Multiple DNN is supported only for 5GS procedures and is not qualified for EPS Session using SBI interfaces.

The SMF supports virtual DNN mapping based on a subscriber profile. It supports mapping of a UE-requested DNN to a configured DNN and sends the selected DNN profile towards the configured network interfaces.

DNN Case Insensitive Support

The DNN configuration in SMF is case insensitive. The configuration accepts a string from 1 through 62 alphanumeric characters, that is case insensitive. It can also contain dots (.) and/or dashes (-).

This enhancement is extended to support all DNN configurations and validations.

IPv6 Interface ID Generation

In releases prior to 2021.01, the SMF generated the IPv6 interface ID in EUI-64 format based on configured or default virtual-mac under DNN. The interface ID is common for all subscribers under DNN. This operation resulted in apps like Google Duo to reject connections due to security policy.

In release 2021.01 and later, the SMF generates unique 64-bit interface ID which is non-EUI-64 format by using SBI VIP address and CommonId of the subscriber.

That is, IPv6 interface ID = VIP-IP (4 bytes) + CommonId (4 bytes)

By default, virtual-mac CLI command is now disabled under DNN configuration.

Interface ID for Different Messages

Call Model

PDU Session Establishment Accept

Create Session Response

5G

N11-SBI-VIP+CommonID

Not Applicable

4G

Not Applicable

GTP-VIP+CommonID

WiFi

Not Applicable

GTP-VIP+CommonID

5G->4G

Not Applicable

Not Applicable (N26 HO - there are NAS contents during handover)

4G->5G

Not Applicable (N26 HO - there are NAS contents during handover)

Not Applicable

4G->WiFi

Not Applicable

GTP-VIP+CommonID (Same as 4G)

WiFi->4G

Not Applicable

GTP-VIP+CommonID (Same as 4G)

5G->WiFi

Not Applicable

N11-SBI-VIP+CommonID (Same as 5G)

WiFi->5G

GTP-VIP+CommonID (Same as WiFi)

Not Applicable