23.1393GPP3GPP system - fixed broadband access network interworkingRelease 17Stage 2TS
This clause shows the combined call flow for a handover from 3GPP Access with GTPv2 or PMIPv6 based S5/S8 interface to a Fixed Broadband Access network via GTPv2 or PMIPv6 based S2b interface. In addition, the procedures for the IP session establishment for NS-WLAN offload using the Fixed Broadband Access network are also integrated into the combined procedures.
Figure 7.9-1: Handover from 3GPP Access to Fixed Broadband Access
If dynamic policy provisioning over S9a is not deployed, the optional steps 5, 7 and 8 do not occur. Instead, the Fixed Broadband Access network may employ local policies.
For connectivity to multiple PDNs, step 8 shall be repeated for each PDN the UE is connected to. Step 8 can occur in parallel for each PDN. Other impacts related to the handover for multiple PDNs are described in TS 23 402  clause 8.1.
Handover is only applicable to the EPC-routed PDN connections. For the NS-WLAN offloaded traffic, a new IP session in fixed broadband access network will be established.
1-2. The description of these steps are is same as for steps 1-2 in TS 23 402 , clause 8.2.3.
3-4. The description of these steps is the same as for steps 1-2 in Figure 7.2-1.
5. This step describes PCC signalling to provision policies for offloaded traffic and are only triggered when the BPCF receives the IMSI and the allocated UE local IP address using Fixed Broadband Access procedures. The description of this step is the same as for steps 3-5 in Figure 7.2-1.
6. The description of PDN Connection setup and Gateway Control Session setup is the same as for steps 3-5 in Figure 7.2-1 with following additions:
– Step 3 in Figure 7.2-1 is mandatory when performing handover from E-UTRAN to Fixed Broadband Access.
– If the UE supports IP address preservation during the handover, the UE shall include its address (IPv4 address or IPv6 prefix /address or both) allocated when it’s attached to 3GPP Access into the CFG_Request sent to the ePDG during IKEv2 message exchange. The ePDG shall include the received UE address in the Create Session Request message or Proxy Binding Request message, and set the HO flag when sending to the PDN GW.
7. The description of this step is the same as for step 6 in Figure 7.2-1.
8. For connectivity to multiple PDNs, the UE establishes connectivity to each PDN that is being transferred from 3GPP access, besides the PDN connection that was established in the steps 5-6, by executing the UE-initiated Connectivity to Additional PDN procedure specified in clause 7.5.
9. The description of this step is the same as for steps 11 in TS 23 402 , clause 8.2.3.