Question: What action should a GTP-U entity take when it receives a Recovery Time Stamp value from a peer GTP-U entity that is smaller than the previously stored value for that peer?
Option 1: Update the stored Recovery Time Stamp value with the newly received value, indicating the peer has restarted.
Option 2: Discard the new Recovery Time Stamp value and log an error due to a possible race condition.
Option 3: Send an Echo Response message without updating the stored Recovery Time Stamp value.
Option 4: Initiate a restart of its own GTP-U contexts.
Explanation: According to the GTP-U based restart procedure, if the received Recovery Time Stamp value is smaller than the previously stored value, it indicates a possible race condition, not a restart. In this case, the receiving entity should discard the new Recovery Time Stamp value and may log an error.