Node to node interrupt mechanism in a multi-processor system

An interrupt mechanism handles an interrupt transaction between a source processor and a target processor on separate nodes in a multi-processor system. The nodes are connected to a network through node interface controls between the node and the network. The transaction begins by initiating the interrupt transaction at the source processor. The interrupt mechanism detects if the target processor is at a remote node on a system bus across the network, and if it is the mechanism sends an ignore signal to the source processor. Then the mechanism suspends the interrupt transaction at the source processor if it detects the target processor is at a remote node. The mechanism performs an ACK/NACK (acknowledge/non-acknowledge) operation at the target processor and returning an ACK signal or a NACK signal to the source processor across the network. This ACK/NACK signal wakes-up the source processor. The source processor sends interrupt data to the target processor if an ACK signal is received and aborts the interrupt transaction if a NACK signal is received.