Creation and management of destination ID routing structures in multi-host PCI topologies

A computer program product for managing routing of data in a distributed computing system, the computer program product comprising:

• a computer usable storage medium having encoded therein computer usable program code executed on a computer;
• computer usable program code configured to determine a physical tree indicative of a physical configuration of the distributed computing system;
• computer usable program code configured to create a virtual tree from the physical tree by copying the physical tree, wherein a configuration of the virtual tree is a same configuration as the physical configuration;
• computer usable program code configured to enable modification of the virtual tree to change an association between at least one source device and at least one target device in the virtual tree to form a modified virtual tree;
• and
• computer usable program code configured to validate the changed association between the at least one source device and the at least one target device in the modified virtual tree to enable routing of data from the at least one source device to the at least one target device, wherein the changed association in the modified virtual tree must be validated to allow access between the at least one source device and the at least one target device.