3GPP 23.501 v20.2.0 — the document's own text

5.9.6 Data Network Name (DNN)

Taught in 7. Every name the system uses (The 5G system architecture, in depth), 4. Knowing who you are and where you are (The 5G system architecture, overview).

A DNN is equivalent to an APN as defined in TS 23.003 [19]. Both identifiers have an equivalent meaning and carry the same information.

The DNN may be used e.g. to:

Select a SMF and UPF(s) for a PDU Session.
Select N6 interface(s) for a PDU Session.
Determine policies to apply to this PDU Session.

The wildcard DNN is a value that can be used for the DNN field of Subscribed DNN list of Session Management Subscription data defined in clause 5.2.3.3 of TS 23.502 [3].

The wildcard DNN can be used with an S-NSSAI for operator to allow the subscriber to access any Data Network supported within the Network Slice associated with the S-NSSAI.