3.1.5.3 Receiving an EstablishConnection Packet
If the SessionState ADM element is not set to WAITING_EC_MSG or WAITING_ECR_MSG, the protocol MUST close the session as specified in Closing a Session (section 3.1.5.9).
An EstablishConnection Packet (section 2.2.3) is a connection request from the initiator or a response to an EstablishConnection Packet sent from this protocol, as specified in Sending an EstablishConnection Request Packet (section 3.1.5.2.3).