Behavior Change

The behavior of UPF has changed in the following scenarios for a converged core call when:

  • N4 and SxA are on the same UPF

  • S-GW relocation is triggered where target SGW-u is same as that of source SGW-u

  • SMF initiates N4 Modification to update downlink FAR with new TEID and IP

  • 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:

  • 1. If SMGR-ID in TEID does not match, then UPF marks the N4 call as non-combo and updates FAR.

  • 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.