Multicast data distribution system

Claim 2

A reliable, high performance data communica­tion system comprising: data source means for assembling data into data packets and transmitting respective said data packets as they become full, or if not full, at the occurrence of a reference interval of time, each of said data packets having data corresponding to data packet sequencing data and an information field; a plurality of receiver means for receiving said transmitted data packets, each said receiver means having failure detection means for checking for failures in the reliable receipt of said data packets by monitoring: said data packet sequenc­ing data; and receipt of a respective data packet at at least a minimum frequency defined by said reference interval of time.

Claim 3

A data communication system as claimed in claim 1, wherein said reference time corresponds to the lapse of a predetermined amount of time which is measured from the transmission of the preceding data packet.

Claim 4

A data communication system as claimed in Claim 1 or 2, further comprising: recovery means for supplying a copy of a respective said data packet to respective re­ceiver means which issue a request for such in response to a determination that there was a failure in the reliable receipt of said data packet.

Claim 5

A data communications system as claimed in Claim 3, wherein said data packet sequencing data corresponds to a data packet sequencing number.

Claim 6

A data communications system as claimed in Claim 4, wherein said respective receiver means identify a respective said data packet being requested by using said data packet sequencing number.

Claim 7

A data communications system as claimed in Claim 3, 4 or 5, wherein said recovery means includes: server memory means for storing copies of a predetermined number of the most current data packets which have been transmitted; and request means being capable of communi­cation with said data source means, said request means for requesting retransmission of a particular data packet from said data source means in the event said recovery means is unable to satisfy a respective receiver's request for a particular data packet from said server memory means, or, in the event that more than a predetermined number of respective receivers issue a request for the same particular data packet.

Claim 8

A data communication system as claimed in Claim 1, or one of Claims 2 - 6, wherein each of said data packets additionally has data corresponding to error checking data, and wherein said receiver means performs a further check for the reliable receipt of said data packets using said error checking data.

Claim 9

A data communication system as claimed in Claim 1, or one of Claims 2 - 7, wherein said receiver means further includes: buffer means for storing said data packets received from said data source means.

Claim 10

A data communication system as claimed in Claim 7 or 8, wherein said receiver means further includes: data management means for selectively accessing the data in said data packets stored in said buffer means.

Claim 11

A data communication system as claimed in Claim 9, wherein said receiver means further includes: data processing means for processing and performing operations using said selected data and means to trigger such processing upon the arrival of appropriate data.

Claim 12

A data communication system as claimed in Claim 1 or anyone of the preceding Claims 2 - 10, wherein each of said data packets has data corresponding to time stamp data.

Claim 13

A data communication system as claimed in Claim 1, or anyone of the preceding Claims 2 - 11, wherein said information field of a respective data packet has a plurality of data items, each of said data items being comprised of data corresponding to a code field and corresponding information field.

Claim 14

A data communication system as claimed in Claim 1, or anyone of the preceding Claims 2 - 12, wherein the said data packet contains a receiver subclass code to allow a plurality of independent packet streams.

Claim 15

A reliable, high performance data communica­tion system comprising: data source means for assembling data into data packets and transmitting respective said data packets as they become full, or if not full, at the occurrence of a predetermined interval of time which is measured from the transmission of the preceding data packet, each of said data packets having data corresponding to data packet sequencing data and an information field; a plurality of receiver means for receiving said transmitted data packets, each said receiver means having failure detection means for checking for failures in the reliable receipt of said data packets by monitoring: said data packet sequenc­ing data; and receipt of a respective data packet at at least a minimum frequency defined by said predetermined interval of time; and recovery means for supplying a copy of a respec­tive said data packet to respective receiver means which issue a request for such in response to a determination that there was a failure in the reliable receipt of said data packet.

Claim 16

A reliable, high performance data communica­tion system comprising: data source means for assembling data into data packets and transmitting respective said data packets as they become full, or if not full, at the occurrence of a predetermined interval of time which is measured from the transmission of the preceding data packet, each of said data packets having data corresponding to data packet sequencing data and an information field; a plurality of receiver means for receiving said transmitted data packets, each said receiver means having failure detection means for checking for failures in the reliable receipt of said data packets by monitoring: said data packet sequenc­ing data; and receipt of a respective data packet at at least a minimum frequency defined by said predetermined interval of time; and recovery means for supplying a copy of a respec­tive said data packet to respective receiver means which issue a request for such in response to a determination that there was a failure in the reliable receipt of said data packet.

Claim 17

A reliable, high performance data communication system comprising: a communications network interconnecting a data source means with a file server means and a plurality of receiver means; said data source means periodically broadcasting packets of information to said file server means and said plurality of receiver means; each said packet including a packet sequence number, a time stamp, and a plurality of information fields, each information field including a unique code field and a corresponding data field; a ring buffer in each said receiver means for storing a plurality of packets received over said communications network; data management means for performing a code selection function in each said receiver means for selecting from said plurality of information fields in each packet stored in said ring buffer, data fields corresponding to selected ones of said unique codes; an ordered data table means in each said receiver means for storing in an ordered sequence said selected data resulting from performance of said code selection function; data processing means in each receiver means for utilizing said selected data in said ordered data table means; said file server means storing all of said packets received from said communications network; negative acknowledgement means in each said receiver means for anticipating the receipt of said periodic packets from said data source means and detecting the omission of an anticipated receipt of a data packet, and in response thereto, generating a request for retransmission to said file server means, which performs retransmission through either a broadcast or via a session type connection; whereby a high performance, reliable data communication from said data source means to said receiver means is established.

Claim 18

A reliable, high performance data communication system comprising: a communications network interconnecting a data source means with a file server means and a plurality of receiver means; said data source means periodically broadcasting packets of information to said file server means and said plurality of receiver means; each said packet including a packet sequence number, a time stamp, and a plurality of information fields, each information field including a unique code field and a corresponding data field; a ring buffer in each said receiver means for storing a plurality of packets received over said communications network; data management means for performing a code selection function in each said receiver means for selecting from said plurality of information fields in each packet stored in said ring buffer, data fields corresponding to selected ones of said unique codes; an ordered data table means in each said receiver means for storing in an ordered sequence said selected data resulting from performance of said code selection function; data processing means in each receiver means for utilizing said selected data in said ordered data table means; said file server means storing all of said packets received from said communications network; negative acknowledgement means in each said receiver means for anticipating the receipt of said periodic packets from said data source means and detecting the omission of an anticipated receipt of a data packet, and in response thereto, generating a request for retransmission to said file server means, which performs retransmission through either a broadcast or via a session type connection; whereby a high performance, reliable data communication from said data source means to said receiver means is established.

Claim 19

The data communication system of Claim 15, wherein said file server means performs a negative acknowledgement assessment function for determining whether the negative acknowledgements from a subplurality of said plurality of receiver means is likely to indicate a failure of the broadcasting of a packet from said data source means to said receiver means; and wherein said file server means further comprises request means for establishing a communications session between said file server means and said data source means in response to the indication from said negative acknowledgement assessment function, for accessing a packet of information from said data source means corresponding to said failed broadcast.

Claim 20

The data communication system of Claim 15 or 16 wherein said data management means performs a change assessment function for accessing data stored in said ordered data table means, and determining whether changes in the value of said data corresponding to a selected code, are greater than a predetermined threshold value; said ordered data table means being responsive to said change assessment function for outputting new values of data identified as surpassing said threshold; and said data processing means being responsive to the output from said ordered data table means to execute tasks corresponding to said changed data which has surpassed said threshold value.

Claim 21

The data communication system of Claim 15, 16 or 17, which further comprises: said periodic broadcast of said data packets by said data source means being based upon a reference interval of time wherein a next data packet is required to be broadcast at the end of said reference interval of time as measured from the broadcast of the most recent data packet; whereby said data source does not fail to broadcast a data packet less frequently than once per said reference interval of time.

Claim 22

The data communication system of Claim 15, or one of Claims 16 - 18, wherein said communication network includes a token ring local area network.

Claim 23

The data communication system of Claim 15, or one of Claims 16 - 19, wherein said negative acknowledgment means of respective receiver means issue said request for retransmission in response to the detection of the expiration of a reference interval of time as measured from the receipt of the most recent packet, or in response to a determination of a missing packet sequence number, or in response to the absence of an anticipated periodic packet which has not been received from said data source means.