Given the log entry '%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up', what is the severity level?

The severity level in Cisco IOS log messages is indicated by the number immediately following the facility (e.g., LINEPROTO). In the given log entry, %LINEPROTO-5-UPDOWN, the number '5' corresponds to the notification severity level. This level indicates normal but significant conditions, such as interface up/down transitions, that do not require immediate action but are worth noting. emergency (0): System unusable. alert (1): Immediate action needed. critical (2): Critical conditions. notification (5): Normal but significant conditions. The other options represent higher severity levels that would be indicated by smaller numbers (0, 1, or 2) in the log message.