Retry filter and circulating echo method and apparatus

摘要

A retry filter and circulating echo apparatus and method are provided for a digital processing system of the type having multiple nodes that communicate via one or more unidirectional rings. The nodes of a digital processing system communicate packets to each other over a unidirectional ring bus. An origination node allocates a sequence identification and transmits a packet to a destination node, which generates a first echo packet and also sets a packet filter indication to drop any further copies of that packet. The first echo packet is sent to the origination node as a confirmation. The origination node generates a second echo packet and sends the generated second echo packet onward to the destination node again as an indication that the packet will not be retransmitted. The destination node transmits a third echo packet as an indication that the sequence can be deallocated.