Method of and apparatus for protecting against and correcting errors in data packet flow streams in closed ring sequential address generators and the like and in other data pack flow paths, without data flow stream interruption

In an address generating system for receiving address requests for a stream of data packet headers received by a traffic manager, the method of generating a corresponding stream of address data, that comprises, providing two identical but independently operated closed rings of successively connected and clocked address generators;

• synchronizing the operation of both address generator rings;
• applying the same received stream of data packet headers from the traffic manager to each of the address generator rings successively to generate requests for identical address data along each address generator ring and to return to the traffic manager identical address responses;
• linking the rings such that when address data arrives from an address generator at an end of the ring, it is stored to await the corresponding address data from the corresponding address generator of the other ring for comparison;
• in the event that such address data from one of the rings is in error and thus different from the corresponding correct address data from the other ring, discarding the erroneous address data and inserting the correct address data from the other ring in its place;
• and re-synchronizing the operation of both rings to enable continual real-time flow of the stream of address data corrected to substitute the correct address data for the erroneous address data.

A fault-tolerance method for protecting against and correcting errors in packet data stream flow, that comprises applying the same packet data stream to each of a pair of independent parallel data flow paths;

• initially synchronizing the flow in the paths;
• linking he paths at predetermined intervals and comparing the corresponding data in each path at such linking in order to detect a possible error in the data occurring in one of the paths;
• substituting for such data error in one of the paths the corresponding correct data from the other path;
• and re-synchronizing the flow in the paths to enable continuation of the data stream flow without interruption and without error.

An address generating system for receiving address requests for a stream of data packet headers received by a traffic manager, having, in combination, two identical but independently operated parallel closed rings of successively connected and respectively clocked sequential address generators;

• means for synchronizing the operation of both address generator rings;
• traffic manager for applying the same stream of data packet headers to each of the address generator rings successively to generate requests for identical address data along each address generator ring and to return to the traffic manager identical address responses;
• means for linking ends of the rings such that when address data arrives from an address generator at an end of the ring, it is stored to await the corresponding address data from the corresponding address generator of the other ring for comparison:
• in the event that such address data from one of the rings is in error and thus different from the corresponding correct address data from the other ring, means discarding the erroneous address data and inserting the correct address data from the other ring in its place;
• and means for re-synchronizing the operation of both rings to enable continual real-time flow of the stream of address data corrected to substitute the correct address data for the erroneous address data.

In the flow along a first path from a source of a stream of successively clocked data packets each provided with headers including error detection code facility, apparatus for correcting data error in a packet and substituting therefor a correct data packet without interrupting the flow of the stream of data packets along said path, having, in combination, means for simultaneously flowing from said source a second identical stream of the successive data packets along a separate parallel second path;

• means for synchronizing the operation of said first and second data packet flow paths;
• means located at intervals along the separate data packet flows, convergingly linking the first and second flow paths and comparing the corresponding data packets from each flow path at such link;
• in the event that one of the compared data packets of one of the flow paths has been determined by its error detection code to be an error, means for discarding such erroneous data packet and using the corresponding data packet of the other flow path in substitution therefore;
• and means for re-synchronizing the operation of the first and second data packet flow paths to continue an uninterrupted stream of data packet flow following such convergence.