Handling of WPS Session at UPF over Sxa Interface
CnSGW handles WPS sessions at UPF over the Sxa Interface in the following ways:
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Selects the message priority that is defined for the PFCP interface under the message-priority profile. For example, Priority value 0 is considered as the highest priority and 15 is considered as the lowest priority.
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This priority gets passed to the UPF in the PFCP header.
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UPF uses this priority during session recovery for early recovery of WPS sessions.
NoteFor collocated subscribers UPF expects that cnSGW and SMF selects the same message priority for recovering these sessions at the same time.-
If there are multipdn calls, where one of the PDN is WPS and the other PDN is non-WPS, then cnSGW selects WPS Priority for WPS PDN only.
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If there are collocated calls, cnSGW selects WPS priority and SMF selects non-WPS priority for a session. In such cases UPF uses the highest priority for collocated session recovery. This way UPF makes sure that both sessions are recovered at the same time.
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