6.7 IP flow mobility triggered by RAN WLAN interworking
23.1613GPPNetwork-Based IP Flow Mobility (NBIFOM)Release 17Stage 2TS
6.7.1 IP flow mobility triggered by Access Stratum indication move-to-WLAN in Trusted WLAN access
6.7.1.0 General
The procedure is used in Network-initiated NBIFOM mode when the UE applies RAN-assisted WLAN interworking (i.e. RAN Rules) or RCLWI and the Access Stratum indicates that the UE shall move traffic to WLAN when the UE is connected simultaneously to 3GPP and TWAN access.
6.7.1.1 Single-connection mode
Figure 6.7.1.1-1: Procedure for Access Stratum indication move-to-WLAN via E-UTRAN using GTP S2a in SCM
The procedure is similar to IP flow mobility triggered by indication move-from-WLAN call flows in Figure 6.7.3-1, with the following differences:
– Step 2 Access Stratum indicates move-to-WLAN.
– Step 3 to Step 6, the move-to-WLAN indication is sent from the UE to the PCRF instead of move-from-WLAN indication.
Figure 6.7.1.1-2: Procedure for Access Stratum indication move-to-WLAN via UTRAN using GTP S5/S8 in SCM
The procedure is similar to IP flow mobility triggered by Access Stratum indication move-from-WLAN call flows in Figure 6.7.3-2, with the following differences:
– Step 2 Access Stratum indicates move-to-WLAN.
– Step 3 to Step 6, the move-to-WLAN indication is sent from the UE to the PCRF instead of move-from-WLAN indication.
6.7.1.2 Multi-connection mode
Figure 6.7.1.2-1: Procedure for Access Stratum indication move-to-WLAN for GTP S2a in MCM
1. The UE is connected simultaneously to 3GPP and TWAN accesses. If, based on clause 5.4, the UE determines for non-radio related reasons that the WLAN access cannot be used, steps 3 to 6 are not performed.
2. Access Stratum indicates move-traffic-to-WLAN.
3. The UE sends the WLCP PDN Modification Command message including a move-to-WLAN indication.
4. The indication is sent to the PDN GW within a Bearer Resource Command.
5. When the PCRF has subscribed to such notification, the PDN GW sends the indication to the PCRF.
The PCRF may update the PCC rules, e.g. by changing the Routing Access Type of PCC Rules and provides the updated PCC rules to the PDN GW.
6. The PDN GW provides updated Routing Rules to the UE based on the updated PCC rules received from PCRF. The PDN GW may initiate dedicated bearer activation and/or modification procedure as described in WLAN according to if the IP flow shall be transported to new dedicated bearer or to existing bearer. In case IP flows are moved from 3GPP access to WLAN, the PDN GW may release the resource in the 3GPP access network. These procedures are described as per Figure 6.3.2.2.2-1 from Steps 3 to 8.
6.7.2 IP flow mobility triggered by Access Stratum indication move-to-WLAN in Untrusted WLAN access
The procedure is used in Network-initiated NBIFOM mode when the UE applies RAN-assisted WLAN interworking (i.e. RAN Rules) or RCLWI, and the Access Stratum indicates that the UE shall move traffic to WLAN when the UE is connected simultaneously to 3GPP and untrusted WLAN access.
Figure 6.7.2-1: Procedure for Access Stratum indication move-to-WLAN for GTP S2b
1. The UE is connected simultaneously to 3GPP and untrusted WLAN accesses.
2. Access Stratum indicates move-traffic-to-WLAN. If, based on clause 5.4, the UE determines for non-radio related reasons that the WLAN access cannot be used, steps 3 to 6 are not performed.
3. The UE sends the IKEv2 INFORMATIONAL Request message including a move-to-WLAN indication.
3a. The ePDG sends an IKEv2 INFORMATIONAL Response message to the UE.
4. The ePDG sends the indication to the PDN GW within a Bearer Resource Command.
5. When the PCRF has subscribed to such notification, the PDN GW sends the indication to the PCRF.
The PCRF may update the PCC rules, e.g. by changing the Routing Access Type of PCC Rules and provides the updated PCC rules to the PDN GW.
6. The PDN GW provides updated Routing Rules to the UE based on the updated PCC rules received from PCRF. The PDN GW may initiate dedicated bearer activation and/or modification procedure in untrusted WLAN access according to if the IP flow shall be transported to new dedicated bearer or to existing bearer. In case IP flows are moved from 3GPP access to WLAN, the PDN GW may release the resource in the 3GPP access network. These procedures are described as per Figure 6.3.2.3-1 from Steps 3 to 9.
6.7.3 IP flow mobility triggered by indication move-from-WLAN
The procedure is used in Network-initiated NBIFOM mode when the UE applies RAN-assisted WLAN interworking (i.e. RAN Rules) or RCLWI, and the Access Stratum indicates that the UE shall move traffic from WLAN.
Figure 6.7.3-1: Procedure for Access Stratum indication move-from-WLAN via E-UTRAN using GTP S5/S8
1. The UE is connected simultaneously to 3GPP and WLAN accesses.
2. Access Stratum indicates move-traffic-from-WLAN.
3. The UE sends the Request Bearer Resource Modification message including a move-from-WLAN indication.
4. The MME sends the indication the SGW within a Bearer Resource Command.
5. The SGW transfers the indication to the PDN GW within a Bearer Resource Command.
6. The PDN GW sends the indication to the PCRF.
The PCRF may update the PCC rules, e.g. by changing the Routing Access Type of PCC Rules and provides the updated PCC rules to the PDN GW.
7. The PDN GW provides updated Routing Rules to the UE based on the updated PCC rules received from PCRF. The PDN GW may initiate dedicated bearer activation and/or modification procedure in WLAN access according to if the IP flow shall be transported to new dedicated bearer or to existing bearer. In case IP flows are moved from WLAN access to 3GPP, the PDN GW may release the resource in the WLAN access network. These procedures are described as per Figure 6.3.2.3-1 from Steps 3 to 7.
Figure 6.7.3-2: Procedure for Access Stratum indication move-from-WLAN via UTRAN using GTP S5/S8
1. The UE is connected simultaneously to 3GPP and WLAN accesses.
2. Access Stratum indicates move-traffic-from-WLAN.
3. The UE sends the Modify PDP Context Request message including a move-from-WLAN indication.
4. The SGSN sends the indication the SGW within a Bearer Resource Command.
5. The SGW transfers the indication to the PDN GW within a Bearer Resource Command.
6. The PDN GW sends the indication to the PCRF.
The PCRF may update the PCC rules, e.g. by changing the Routing Access Type of PCC Rules and provides the updated PCC rules to the PDN GW.
7. The PDN GW provides updated Routing Rules to the UE based on the updated PCC rules received from PCRF. The PDN GW may initiate dedicated bearer activation and/or modification procedure in WLAN access according to if the IP flow shall be transported to new dedicated bearer or to existing bearer. If IP flows are moved from WLAN access to 3GPP, the PDN GW may release the resource in the WLAN access network. These procedures are described according to Figure 6.3.2.1-2 from Steps 3 to 7.