A computer system may include a directory, several active devices configured to access data, an address network configured to convey address packets point-to-point between the active devices and the directory, and a data network configured to convey data between the active devices and the directory. The address network may include a response virtual network configured to convey response packets and a multicast virtual network configured to convey invalidating packets. A first active device may be configured to transition an ownership responsibility for a coherency unit upon receipt of a response packet and to transition an access right to the coherency unit upon receipt of a corresponding data packet. The ownership responsibility for the coherency unit transitions at a different time than the access right to the coherency unit transitions.