A node includes several devices including a memory, an active device, and an interface configured to send and receive coherency messages on an inter-node network coupling the node to another node, as well as an address network that communicates address packets between the devices. In response to receiving a coherency message that requests an access right to a coherency unit, the interface sends a proxy packet on the address network. In response to the proxy packet, the memory sends the interface data corresponding to the coherency unit and an indication of the global access state of the coherency unit within the node if the global access state is not the modified state. Otherwise, the memory sends an additional proxy packet on the address network. If the active device is the owner of the coherency unit, the active device ignores the proxy packet and responds to the additional proxy packet.