4.23.17 Additional considerations for Home-routed roaming

23.5023GPPProcedures for the 5G System (5GS)Release 18TS

As described in clause 4.23.1, the procedures in clause 4.23 apply for home-routed roaming scenarios with V-SMF insertion/removal/change (i.e. by replacing the I-SMF with V-SMF and SMF with H-SMF). Differences compared to the procedures for I-SMF are described below:

– The Registration procedure as defined in clause 4.23.3 with the following additions:

– Step 8a of clause 4.23.4.3 (for cases d and e): the new V-SMF provides the QoS constraints of the VPLMN to H-SMF.

– Step  8c of clause 4.23.4.3 (for cases d and e): the new V-SMF may apply VPLMN QoS policies as described in TS 23.501 [2], clause 5.7.1.11.

– Inter NG-RAN node N2 based handover with V-SMF insertion/change as defined in clause 4.23.7.3 (i.e. by replacing the I-SMF with V-SMF) with the following additions:

– Preparation phase, step 4b (for case V-SMF change): the target V-SMF may apply VPLMN QoS policies as described in TS 23.501 [2], clause 5.7.1.11.

– Preparation phase, step 5d (for case V-SMF insertion): the target V-SMF may apply VPLMN QoS policies as described in TS 23.501 [2], clause 5.7.1.11.

– Execution phase, step 6 (for case V-SMF change/insertion): the target V-SMF provides the QoS constraints of the VPLMN to H-SMF.