Patent ID: 7669013

Claim:
A computer implemented method for maintaining cache coherency in a multi-node system, the computer implemented method comprising: responsive to receiving a request at a multi-node bridge of a local node, performing a look-up of a directory in the local node if the request is a system request; if an entry in the directory of the local node indicates that data specified in the request has a local owner or the request has a local destination, forwarding the request to the local node; determining, at the local node, whether the request is a local request or a system request; responsive to the local node determining that the request is a local request, performing a look-up of the directory in the local node; if the entry in the directory of the local node indicates that data specified in the request has a local owner and the request has a local destination, resolving coherency of the data on the local node and performing a transfer of the data specified in the request if a data transfer is required; and if the entry in the directory of the local node indicates that data specified in the request does not have a local owner or the request does not have a local destination, forwarding the request to all remote nodes in the multi-node system.