The procedure is similar to in clause 126.96.36.199, 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 . 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.
The procedure is similar to GTP based S2a call flows in clause 188.8.131.52, 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 184.108.40.206. 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 220.127.116.11.