Behavior Change
The behavior of UPF has changed in the following scenarios for a converged core call when:
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N4 and SxA are on the same UPF
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S-GW relocation is triggered where target SGW-u is same as that of source SGW-u
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SMF initiates N4 Modification to update downlink FAR with new TEID and IP
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UPF uses the TEID and finds the target Sxa session
Previous Behavior: If the Sxa session was not found, then UPF updated FAR and retained the N4 call as combo only.
New Behavior: UPF inspects SMGR-ID in TEID:
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1. If SMGR-ID in TEID does not match, then UPF marks the N4 call as non-combo and updates FAR.
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2. If SMGR-ID matches and the corresponding Sxa session is not present, then UPF rejects N4 Modification with cause Mandatory IE Incorrect and faulty IE Outer Header Creation.