Question: Upon discovery of a link failure in an LTE-WLAN setup, what action is taken regarding the S-KWT (Security Key for Wireless Termination) on both the User Equipment (UE) and the evolved NodeB (eNB)?
Option 1: The UE updates the S-KWT, while the eNB instructs the WLAN Termination (WT) to retain the existing S-KWT.
Option 2: The UE retains the S-KWT, but the eNB signals the WT to generate a new S-KWT.
Option 3: The UE deletes the S-KWT, and concurrently, the eNB indicates to the WT to delete the S-KWT.
Option 4: The UE and eNB both independently decide whether to retain or update the S-KWT based on internal policies.
Explanation: Upon detecting a link failure in either the WLAN or LTE connection, security best practices dictate removing potentially compromised security keys. Thus, both the UE (directly) and the eNB (by instructing the WT) would delete the S-KWT to ensure security integrity, necessitating a fresh key exchange for future connections.