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A Note for Enabling NetworkInstance IE Encoding for free5GC v3.3.0

Sample Configurations and Miscellaneous for Mobile Network

For free5GC v3.3.0, Network Instance IE of PFCP Session Establishment Request sent from SMF to UPF is not encoded by default. In this case, PFCP Session Establishment may fail between free5GC SMF and other UPF. Therefore, by adding the following line in the free5GC SMF configuration file smfcfg.yaml, the Network Instance IE of PFCP Session Establishment Request can be encoded and sent to the UPF.

configuration:
  ...
  nwInstFqdnEncoding: true <--
  ...

For this, please refer to the followings of 3GPP specifications.

3GPP TS 29.244 Interface between the Control Plane and the User Plane nodes
- 8 Information Elements
  - 8.2 Information Elements
    - 8.2.4 Network Instance

3GPP TS 23.003 Numbering, addressing and identification
- 9A Definition of Data Network Name
  - 9.1 Structure of APN

The encoding of the APN shall follow the Name Syntax defined in RFC 2181 [18], RFC 1035 [19] and RFC 1123 [20].
The APN consists of one or more labels. Each label is coded as a one octet length field followed by that number of
octets coded as 8 bit ASCII characters. Following RFC 1035 [19] the labels shall consist only of the alphabetic
characters (A-Z and a-z), digits (0-9) and the hyphen (-). Following RFC 1123 [20], the label shall begin and end with
either an alphabetic character or a digit. The case of alphabetic characters is not significant. The APN is not terminated
by a length byte of zero.