Provided are a connection management mechanism and a connection management method with which computer bus connections can be managed such that failures and freezes do not occur in a computer system when delays and packet losses occur. A connection management unit, which is used in computer bus communication in which packets are transmitted between a request source and a request destination, has a dummy return packet generation/transmission function wherein a dummy return packet is generated and is transmitted to the request source when a delay or loss occurs in a return packet transmitted from the request destination, and/or a filter function wherein, after transmission of the dummy return packet, a legitimate return packet arriving from the request destination is discarded.