Configuring Session Type

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