Configuring SSC Mode
To configure the Session and Service Continuity Mode parameters in the DNN profile, use the following sample configuration:
config
profile dnn dnn_name
ssc-mode sscmode_value [ allowed allowed_sscmode_value ]
exit
NOTES:
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profile dnn dnn_name : Enter the DNN profile configuration mode.
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ssc-mode sscmode_value [ allowed allowed_sscmode_value ] : Configure the SSC mode parameters.
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ssc-mode sscmode_value : Specify the default SSC mode. sscmode_value must be an integer in the range of 1–3.
The SMF supports only SSC mode-1.
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allowed allowed_sscmode_value : Specify the allowed SSC modes. Up to two modes can be configured in addition to the default SSC mode. allowed_sscmode_value must be an integer in the range of 1–3.
If the UEs are sent with SSC mode values defined under allowed command, then these values are supported along with the default SSC mode supported for the DNN profile.
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no ssc-mode : Specify this command to remove the SSC mode from the DNN profile.
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When UE requests SSC mode-2 or mode-3, if the UE's subscription (in order of priority: UDM or Local configuration on SMF) allows SSC mode-1 along with mode-2 or mode-3, then SMF sends PDU Session Establishment Reject with 5GSM cause 68 (Not supported SSC mode) and Allowed SSC mode as 01. This method allows the UE to retry with SSC mode-1. As per 3GPP TS 24.501, the 5GSM cause 68 is sent when the requested SSC mode is not supported by the subscription.
To honor PDU Session Establishment, the SMF expects SSC mode either through UDM subscription or local configuration. If SMF does not have SSC mode as part of UDM subscription or local configuration, the SMF rejects PDU Session Establishment with 5GSM cause 31 (Request rejected and unspecified).