Guaranteed reliable broadcast network

• US 5,109,384 A
• Filed: 02/27/1990
• Issued: 04/28/1992
• Est. Priority Date: 11/02/1988
• Status: Expired due to Fees

• Current Assignee: Lawrence C.N. Tseung
• Original Assignee: Lawrence C.N. Tseung
• Inventors: Tseung, Lawrence C. N.
• Primary Examiner(s): Atkinson, Charles E.
• Application Number:
  US07/486,082
• Time in Patent Office: 791 Days
• Field of Search: 371/32, 371/33, 371/67.1, 371/68.1, 371/68.2, 340/825.06, 340/825.15, 364/222.2, 364/240.8, 364/240.9, 364/242.6, 364/242.94, 364/242.5
• US Class Current: 714/748
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 1/12 by using return channel
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 12/1868 Measures taken after transmission, e.g. acknowledgments
• CPC Class Codes: H04L 2001/0092 Error control systems characterised by the topology of the transmission link
• CPC Class Codes: H04L 2001/125 Arrangements for preventing errors in the return channel
• CPC Class Codes: H04L 63/04 for providing a confidential data exchange among entities communicating through data packet networks
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32

Abstract

This system guarantees reliable data transmission for one-to-one, one-to-many and/or many-to-many communications among data processing stations over a communications network. A general solution is presented, and a new concept (the arbitrator node) is discussed in detail. Special logical nodes and a new communications protocol are used so that a message is guaranteed to be received if a receiver(s) wants to receive the message even though a receiver(s) may be busy, slow or temporarily powered off. An optional management station controls orderly start and stop of group communications or conferences, and may also handle secure, confidential communications. This guaranteed, reliable, one-to-one, one-to-many or many-to-many system can be applied to overcome previously unsolved problems.

Claims

1. In a method of providing guaranteed reliable data communications over a digital communications network, including the following steps:

(a) monitoring said network for digital messages with an arbitrator node coupled to said network;

(b) reserving network message slots for exclusive use by said arbitrator node; and

(c) transmitting arbitrator messages identifying said messages monitored by said monitoring step (a) during said reserved message slots.

2. A method as in claim 1 wherein said reserving step (b) comprises the step of reserving every mth message slot for said arbitrator node, m being an integer.

3. A method as in claim 1 wherein

said network is of the type including at least one further node connected thereto;

and

said reserving step (b) comprises the step of reserving predetermined message slots beforehand for exclusive use by said arbitrator node and inhibiting said further node from transmitting within said reserved message slots.

4. A method as in claim 1 further including the steps of:

(i) transmitting said digital messages over said network from at least one further node coupled to said network;

(ii) detecting said arbitrator message with said further node; and

(iii) repeating said transmitting step (i) only upon detection by said further node of completion of said arbitrator message.

5. A method as in claim 1 further including the following steps:

(i) transmitting said digital messages with at lest one further node coupled to said network;

(ii) receiving said arbitrator message with said further node;

(iii) comparing, at said further node, said digital messages transmitted by said further node with messages identified by said arbitrator message; and

(iv) retransmitting at said further node, selected ones of said transmitted digital messages said comparing step (iii) reveals have not been identified in said arbitrator message.

6. A method of providing guaranteed reliable data communications over a digital communications network, including the following steps:

(a) monitoring said network for digital messages with an arbitrator node coupled to said network;

(b) transmitting arbitrator messages identifying said messages monitored by said monitoring step (a);

(c) receiving said digital messages and said arbitrator message with a further node connected to said network;

(d) comparing, at said further node, messages received by said further node with messages identified by said arbitrator message; and

(e) retransmitting selected ones of said digital messages in response to the results of said comparison.

7. A method as in claim 6 wherein said arbitrator node performs said retransmitting step.

8. A method as in claim 6 wherein said retransmitting step is performed by a playback recorder node different from said arbitrator node.

9. In a method of providing guaranteed reliable data communications over a digital communications network, including the following steps:

(a) monitoring said network for digital messages with an arbitrator node coupled to said network;

(b) reserving network time intervals for transmission by said arbitrator node; and

(c) transmitting arbitrator messages identifying said messages monitored by said monitoring step (a) during said reserved time intervals.

10. A method as in claim 9 wherein said reserving step (b) comprises the step of periodically reserving said network for exclusive use by said arbitrator node upon elapse of a time interval having duration T.

11. A method as in claim 9 wherein:

said network is of the type including at least one further node connected thereto; and

said reserving step (b) comprises the step of reserving predetermined time intervals beforehand for exclusive use by said arbitrator node and inhibiting said further node from transmitting within said reserved time intervals.

12. A method as in claim 9 further including the following steps:

receiving said digital messages and said arbitrator message with a further node connected to said network;

comparing, at said further node, messages received by said further node with messages identified by said arbitrator message; and

retransmitting selected ones of said digital messages in response to the results of said comparison.

13. A method as in claim 12 wherein said arbitrator node performs said retransmitting step.

14. A method as in claim 12 wherein said retransmitting step is performed by a playback recorder node different from said arbitrator node.

15. A method as in claim 9 further including the steps of:

(i) transmitting said digital messages over said network from at least one further node coupled to said network;

(ii) detecting said arbitrator message with said further node; and

(iii) inhibiting said transmitting step (i) until said further node detects completion of said arbitrator message.

16. A method as in claim 9 further including the following steps:

(i) transmitting said digital messages with at least one further node coupled to said network;

(ii) receiving said arbitrator message with said further node;

(iii) comparing, at said further node, said digital messages transmitted by said further node with messages identified by said arbitrator message; and

(iv) retransmitting, at said further node, selected ones of said transmitted digital messages if said comparing step (iii) reveals said selected messages have not been identified in said arbitrator message.

17. In a method of providing guaranteed reliable data communications over a digital communications network, comprising the steps of:

(a) receiving digital messages from said network with an arbitrator node coupled to said network; and

(b) transmitting an arbitrator message identifying said messages received by said receiving step (a) upon any of;

(i) receipt of a predetermined number of said messages by said receiving step (a), and (ii) the occurrence of a reference point in time if less than said predetermined number of messages have been received upon said occurrence.

18. A method as in claim 17 further including the following steps:

(c) receiving digital messages from said network with a user node;

(d) receiving said arbitrator message with said user node;

(e) comparing, at said user node, the messages identified as having been received by said arbitrator message with said messages actually received by said user node in said receiving step (c); and

(f) selectively requesting retransmission of messages in response to the results of said comparing step (e).

19. In a method of providing guaranteed reliable data communications over a digital communications network, comprising the steps of:

(a) transmitting plural digital messages over said network during corresponding message transmission periods;

(b) inhibiting said transmitting step (a) during recurring message transmission periods reserved for use by an arbitrator node coupled to said network;

(c) receiving said plural messages transmitted by said transmitting step (a) with said arbitrator node; and

(d) during said reserved message transmission periods, transmitting, with said arbitrator node, arbitrator messages identifying said plural messages received by said receiving step (c) since the last time an arbitrator message was transmitted.

20. A method as in claim 19 wherein said transmitting step (d) includes the step of specifying in said arbitrator message the sequence in which said plural messages were received by said receiving step (c).

21. In a method of providing guaranteed reliable data communications to plural nodes connected to a digital communications network, comprising the steps of:

(a) transmitting plural digital messages over said network in a sequence;

(b) receiving said plural messages transmitted by said transmitting step (a) with an arbitrator node coupled to said network;

(c) generating an arbitrator message in response to said plural messages received by said receiving step (b) after m messages (m an integer) have been received by said arbitrator node or upon occurrence of a reference point in time if less than m messages have been received upon occurrence of said reference point in time, said arbitrator message identifying said plural messages received by said receiving step (b); and

(d) transmitting said arbitrator message over said network.

22. A method of providing guaranteed reliable data communications between first, second and third nodes connected to a digital communications network, said method comprising the steps of:

(a) transmitting a first digital message from said first node over said network during a first message slot;

(b) transmitting a second digital message from said second node over said network during a second message slot different than said first message slot;

(c) receiving said first message and said second message with said third node;

(d) storing within said third node at least an identification of said first and second messages received by said receiving step (c);

(e) receiving said first message and said second message with an arbitrator node also coupled to said network;

(f) generating an arbitrator message identifying said messages received by said receiving step (e);

(g) transmitting said arbitrator message over said network during a further message slot;

(h) receiving said arbitrator message with said third node;

(i) comparing the contents of said arbitrator message with said identifications stored by said storing step (d); and

(j) originating a retransmission request message with said third node if said comparing step (i) reveals a discrepancy between the messages received by said receiving step (c) and the messages identified by said arbitrator message.

23. A method as in claim 22 further including the step of reserving beforehand said further message slot for exclusive use by said arbitrator node, said transmitting step (g) transmitting said arbitrator message within said reserved message slot.

24. A method as in claim 22 wherein said reserving step includes the step of preventing each of said first and second nodes from transmitting on said network during said further message slot.

25. A method as in claim 22 wherein said reserving step includes the step of preventing each of said first and second nodes from transmitting from the beginning of said further message slot until said each node detects the termination of transmission of said arbitrator message.

26. In a method of providing guaranteed reliable data communications over a digital communications network, including the following steps:

(a) monitoring said network for digital messages with an arbitrator node coupled to said network;

(b) transmitting an arbitrator message identifying said messages monitored by said monitoring step (a); and

(c) specifying within said arbitrator message a future message slot reserved for said arbitrator node.

27. A method as in claim 26 wherein said transmitting step (b) is performed every mth message slot, m being an integer, and said method further includes the step of varying the value of m.

28. A method as in claim 26 further including the following steps:

receiving said digital messages and said arbitrator message with a further node connected to said network;

comparing, at said further node, messages received by said further node with messages identified by said arbitrator message; and

retransmitting selected ones of said digital messages in response to the results of said comparison.

29. A method as in claim 26 further including the following steps:

(i) transmitting said digital messages with at least one further node coupled to said network;

(ii) receiving said arbitration message with said further node;

(iii) comparing, at said further node, said digital messages transmitted by said further node with messages identified by said arbitrator message; and

(iv) retransmitting, at said further node, selected ones of said transmitted digital messages if said comparing step (iii) reveals said selected messages have not been identified in said arbitrator message.

30. In a method of providing guaranteed reliable data communications over a digital communications network, including the following steps:

(a) monitoring said network for digital messages with an arbitrator node coupled to said network;

(b) transmitting an arbitrator message identifying said messages monitored by said monitoring step (a);

(c) specifying in said arbitrator message a future time interval;

(d) repeating said monitoring step (a) subsequent to said transmitting step (b); and

(e) repeating said transmitting step (b) within said future time interval.

31. A method as in claim 30 wherein said transmitting step (b) is performed periodically upon elapse of a time interval of duration T, and said method further includes the step of varying the value of T.

32. A method as in claim 30 further including the following steps:

receiving said digital messages and said arbitrator message with a further node connected to said network;

comparing, at said further node, messages received by said further node with messages identified by said arbitrator message; and

retransmitting selected ones of said digital messages in response to the results of said comparison.

33. A method as in claim 30 further including the following steps:

(i) transmitting said digital messages with at least one further node coupled to said network;

(ii) receiving said arbitration message with said further node;

(iii) comparing, at said further node, said digital messages transmitted by said further node with messages identified by said arbitrator message; and

(iv) retransmitting, at said further node, selected ones of said transmitted digital messages if said comparing step (iii) reveals said selected messages have not been identified in said arbitrator message.

34. A method of improving the performance of a digital communications network, said method including the following steps:

(a) monitoring said network for digital messages with an arbitrator node coupled to said network;

(b) specifying future message slots for use by other nodes in response to said digital messages; and

(c) transmitting an arbitrator message identifying said reserved future message slots.

35. A method as in claim 34 wherein:

said monitoring step (a) includes the step of determining the message type of a first message appearing on said network; and

said specifying step (b) is conditionally performed based on the message type determined by said determining step.

36. A method as in claim 34 wherein:

said monitoring step (a) includes the steps of accepting some messages and ignoring other messages; and

said specifying step (b) includes the step of reserving future message slots for messages ignored by said ignoring step.

37. A method as in claim 34 further including the following steps:

receiving said digital messages and said arbitrator message with a further node connected to said network;

comparing, at said further node, messages received by said further node with messages identified by said arbitrator message; and

retransmitting selected ones of said digital messages in response to the results of said comparison.

38. A method as in claim 34 further including the following steps:

(i) transmitting said digital messages with at least one further node coupled to said network during times not identified by said arbitrator message as being reserved for other nodes;

(ii) receiving said arbitration message with said further node;

(iii) comparing, at said further node, said digital messages transmitted by said further node with messages identified by said arbitrator message; and

(iv) retransmitting, at said further node, selected ones of said transmitted digital messages during message slots specified by said arbitrator message as being reserved for use by said further node.

39. In a method of providing guaranteed reliable one-to-one data communication over a digital communications network, including the following steps:

(a) transmitting a digital message from a first node to a second node over said network;

(b) receiving said digital message with said second node;

(c) also receiving said digital message with an arbitrator node over said network; and

(d) transmitting, over said network with said arbitrator node, an arbitrator message identifying reception of said digital message.

40. A method as in claim 39 wherein said transmitting step (a) comprises the step of addressing said digital message only to said second node.

41. A method as in claim 39 wherein:

said method further includes the steps of transmitting a further digital message over said network and receiving said further digital message with said second node and with said arbitrator node; and

said transmitting step (d) includes the step of transmitting said arbitrator message identifying reception of said first-mentioned and said further digital messages by said arbitrator node.

42. A method as in claim 39 further including the following steps:

receiving said arbitrator message with said first node; and

retransmitting said digital message from said first node if said arbitrator message does not identify reception of said digital message.

43. A method as in claim 39 further including the following steps:

receiving said arbitrator message with said second node;

comparing, at said second node, said digital message received in said receiving step (b) with said arbitrator message; and

selectively requesting retransmission of said digital message in response to the results of said comparison.

44. In a method of providing reliable data communications based on message priority over a digital communications network, including the following steps:

(a) assigning a message priority for digital messages that are transmitted over said network;

(b) reserving future message slots in response to said message priority assignment with an arbitrator node coupled to said network; and

(c) transmitting at least one arbitrator message with said arbitrator node identifying said reserved future message slots.

45. A method as in claim 44 wherein:

said method further includes the step of monitoring said network with said arbitrator node for digital messages; and

said transmitting step (c) includes the step of transmitting information identifying said messages monitored by said monitoring step.

46. A method as in claim 44 further including the following steps:

receiving said digital messages and said arbitrator message with a further node connected to said network;

comparing, at said further node, messages received by said further node with messages identified by said arbitrator message; and

retransmitting selected ones of said digital messages in response to the results of said comparison.

47. A method as in claim 44 further including the following steps:

(i) transmitting said digital messages with at least one further node coupled to said network;

(ii) receiving said arbitration message with said further node;

(iii) comparing, at said further node, said digital messages transmitted by said further node with messages identified by said arbitrator message; and

(iv) retransmitting, at such further node, selected ones of said transmitted digital messages in response to said comparison.

48. A method as in claim 44 wherein:

said method further includes the step of receiving messages from said network with said arbitrator node and testing said messages for message type; and

said reserving step (d) is performed in response to the type of messages received by said arbitrator node.

49. A method as in claim 44 wherein:

said method further includes the steps of accepting, with said arbitrator node, some messages appearing on said network and ignoring, with said arbitrator node, other messages appearing on said network; and

said reserving step includes the step of reserving future message slots for said messages ignored by said ignoring step.

50. A method of providing guaranteed reliable broadcast data communication to plural digital signal processing stations connected to a digital signal communications network, said method comprising the steps of:

(a) originating a digital signal message;

(b) transmitting said message to a retransmission station;

(c) assigning a global identifier to said message by said retransmission station;

(d) retransmitting said message together with said assigned global identifier to all said plural digital signal processing stations;

(e) testing said message by each said plural station to determine whether the said message has been received before by said station;

(f) retransmitting said message to each of said data processing stations if said testing step (e) reveals said message has not been received before;

(g) repeating said testing step (e) and retransmitting steps (f) until all said plural stations receive the said message.

51. In a method of providing guaranteed reliable communications over a communications network of the type having plural nodes, including at least a first node, coupled thereto, said network communicating a stream of messages, including the following steps:

(a) providing, at said first node, a message to be communicated over said network;

(b) generating a global message sequence identifier;

(c) communicating said global message sequence identifier to said first node; and

(d) broadcasting said message from said first node over said network in a sequence, with respect to said stream of messages, which is responsive to said communicated global message sequence identifier.

52. A method as in claim 51 wherein said broadcasting step includes the step of broadcasting said global message sequence identifier with said message.

53. A method as in claim 52 further including the following steps:

receiving said broadcasted message with a further node coupled to said network; and

determining, in response to said received global message sequence identifier, whether a message previously transmitted in said stream has not been received by said further node.