Method and apparatus for pci bus address based routing with integrated did

A method is provided for creating and managing tables for routing packets through an environment that includes multiple hosts and shared PCI switches and adapters. A Destination Identification (DID) field in the PBA is appended to a transaction packet dispatched through the PCI switches, wherein a particular DID is associated with a particular host or system image, and thus identifies the physical or virtual end point of its packet. In one embodiment, packets are routed through PCI switches in a distributed computer system comprising multiple root nodes, wherein each root node includes one or more hosts. The embodiment includes the step of creating a table or like data structure in a specified one of the switches. When a particular host of one of the root nodes becomes connected to the specified switch, a PCI Configuration Master (PCM), residing in one of the root nodes, is operated to enter a destination identifier or DID into the table. The DID is then appended as an address component, to packets directed through the specified switch from the particular host to one of the adapters. The destination identifier is also used to determine that a PCI packet, routed through the specified switch from one of the adapters, is intended for the particular root node.