Question: In LTE-WLAN integration, what happens to the IPSec tunnel when the last Data Radio Bearer (DRB) between the Evolved Node B (eNB) and a User Equipment (UE) is deleted?
Option 1: A new IPSec tunnel is established for potential future DRBs.
Option 2: The eNB instructs the Lightweight IP Security Gateway (LWIP-SeGW) and the UE to release the IPSec tunnel.
Option 3: The existing IPSec tunnel remains active for a predefined timeout period before being automatically released.
Option 4: The decision to release or maintain the IPSec tunnel is left to the UE's discretion.
Explanation: When the last DRB is deleted, there's no longer a need for the secure IPSec tunnel between the UE and the LWIP-SeGW. Thus, the eNB instructs both parties to release the tunnel, ensuring resource efficiency and security protocol adherence, highlighting coordinated management importance in maintaining secure telecom network connections.