16.7 Detach in WLAN on S2a for Multi-connection Mode

23.4023GPPArchitecture enhancements for non-3GPP accessesRelease 18TS

16.7.1 Detach in WLAN on GTP S2a

16.7.1.1 UE/TWAN Initiated Detach Procedure in WLAN on GTP S2a

Figure 16.7.1.1-1: UE/TWAN-Initiated Detach in WLAN on GTP S2a

The procedure is similar to in clause 16.3.1.1, with the following differences:

– Step1: To detach from EPC, the UE can send a disassociation or deauthentication notification according to IEEE Std 802.11-2012 [64]. If there is no traffic received from the UE for a configurable duration and the TWAN detects the UE has left based on unanswered probes (e.g. ARP Request, Neighbor Solicitation message), the TWAN initiates the detach procedure.

– Step 2 to Step 5 refers to clause 16.9.1.

– In the case of connectivity with multiple PDNs, the steps 2 to 5 are repeated for each PDN the UE is connected to.

16.7.1.2 HSS/AAA Initiated Detach Procedure in WLAN on GTP S2a

Figure 16.7.1.2-1: HSS/AAA-Initiated Detach in WLAN on GTP S2a

The procedure is similar to in clause 16.3.1.2, with the following differences:

– Step 2 refers to Figure 16.7.1.1-1.

16.7.2 Detach in WLAN on PMIP S2a

16.7.2.1 UE/TWAN Initiated Detach Procedure in WLAN on PMIP S2a

Figure 16.7.2.1-1: UE/TWAN Initiated Detach in WLAN on PMIP S2a

The procedure is similar to GTP based S2a call flows in clause 16.7.1.1, with the following differences:

– Step 2 is a Proxy Binding Update. The details of the Proxy Binding Update message are described in step 3 in clause 6.4.1.1. Additionally, the Proxy Binding Update includes the current TWAN Identifier as described in clause 16.1.7, the Timestamp of this TWAN-Identifier and the UE Time Zone.

– Step 5 is a Proxy Binding Acknowledgement. The details of the Proxy Binding Acknowledgement message are described in step 6 in clause 6.4.1.1.

16.7.2.2 HSS/AAA Initiated Detach Procedure in WLAN on PMIP S2a

Figure 16.7.2.2-1: HSS/AAA Initiated Detach in WLAN on PMIP S2a

The procedure is similar to GTP S2a call flow in clause 16.3.1.2, the difference is that step 2 refers to figure 16.7.2.1-1.

NOTE: The HSS/AAA may also send a detach indication message to the PDN GW. The PDN GW does not remove the PMIP tunnels on S2a, since the TWAN is responsible for removing the PMIP tunnels on S2a. The PDN GW acknowledges the receipt of the detach indication message to the 3GPP AAA Server.