Abstract: A node controller (12) includes a local block unit (28) that receives and processes request and reply packets. A request module (30) in the local block unit (28) receives a request packet and determines whether the request packet has an error. If there is no error, the request module (30) forwards local invalidation requests to a invalidation module (32) for processing and forwards programmed input/output read and write requests to a processor module (34) for processing. If an error is detected, the request module (30) forwards the request packet to a registers module (40). The registers module (40) stores the header and data contents of the request packet in header registers (70, 72) and a data register (80). An error bit is corresponding to the identified type of error is set in an error register (50). The request module (40) generates an interrupt signal (52) in response to setting the error bit in the error register (50).