Patent ID: 7606978

Claim:
A system, comprising: a node including one or more active devices, an interface, and an address network configured to transmit address packets between the one or more active devices and the interface; and an additional node coupled to the node by an inter-node network, wherein the additional node includes an additional address network; wherein a given active device having an ownership responsibility for a coherency unit is configured to respond to certain access right requests; wherein in response to receiving from the additional node via the inter-node network, a coherency message requesting an access right to a coherency unit, the interface is configured to send a first type of address packet on the address network if a global access state of the coherency unit in the node is a modified state and to send a second type of address packet on the address network if the global access state of the coherency unit in the node is not the modified state; and wherein if the given active device has an ownership responsibility for the coherency unit, the given active device is configured to ignore the second type of address packet and to respond to the first type of address packet.