An apparatus may comprise a processing resource operatively coupled to a memory resource and a frame determination component operatively coupled to the processing resource and the memory resource. The frame determination component may cause a counter corresponding to a particular station associated to the apparatus to be stored in the memory resource, the counter to be incremented in response to receipt of a transmission frame containing an invalid starting sequence number (SEN) and a deauthentication frame to be transmitted in response to receipt of a threshold number of transmission frames containing the invalid.