This read-write enumerated INTEGER (locked/unlocked) sets the lock mode applied in bulk to the interface range defined by swIfPortLockIfRange, with unlocked meaning MAC addresses are freely learned and locked meaning learning stops and only known sources are forwarded, per the description. Admins use this to enforce port security across a whole group of interfaces in one SNMP set operation instead of configuring each port individually. For example, locking an entire range of guest-network access ports at once prevents new unauthorized devices from being learned across that whole group simultaneously.