Question: What action does the source eNodeB (eNB) take if a UE returns before receiving the UE CONTEXT RELEASE message or the expiry of the timer TX2RELOCoverall, in the context of X2 Application Protocol (X2AP)?
Option 1: Immediately release the UE's resources to accommodate new UEs.
Option 2: Initiate a new handover procedure to another eNB.
Option 3: Stop the TX2RELOCoverall timer and continue serving the UE.
Option 4: Send a failure report to the MME regarding the UE CONTEXT RELEASE.
Explanation: This is because, as per the X2AP protocol for handling abnormal conditions during handovers, if the UE returns to the source eNB before the procedure to release its context is completed (either by message reception or timer expiry), the source eNB should revert to serving the UE. Stopping the TX2RELOCoverall timer and continuing service ensures seamless connectivity for the returning UE, aligning with the protocol's provisions for managing transient conditions in E-UTRAN.