A multi-route connection bridge 24 performs swapping of an address described in a header of network packet to allow a downstream PCI express-network bridge 25 to be connected with a plurality of upstream PCI express-network bridges 21. Also, the multi-route connection bridge 24 configures an I/O resource 3 in advance, maps the configured I/O resource 3 to an address space of each host 1, and swaps header data described in an I/O packet encapsulated to the network packet by using mapping data. Thus, the multi-route connection bridge 24 assigns I/O capability of I/O resource 3 to each host 1 in units of functions to allow the I/O resource 3 to be shared simultaneously by the hosts 1.