System and method for utilizing spare bandwidth to provide data integrity over a bus

• US 7,020,809 B2
• Filed: 09/25/2002
• Issued: 03/28/2006
• Est. Priority Date: 09/25/2002
• Status: Active Grant

• Current Assignee: X Corp. (f/k/a Twitter, Inc.) (X Holdings Corp.)
• Original Assignee: International Business Machines Corporation
• Inventors: Lucas, Gregg Steven, Garcia, Enrique, Medlin, Robert Earl, Ellison, Russell Lee, Jadeja, Rajendrasinh Banesinh, Kleppel, Yvonne Hanson
• Primary Examiner(s): Beausoliel, Robert
• Assistant Examiner(s): GUYTON, PHILIP A
• Application Number:
  US10/255,040
• Publication Number:
  US 20040059967A1
• Time in Patent Office: 1,280 Days
• Field of Search: 714/50, 714/51, 714/52, 714/5, 714/27, 714/30, 710/106, 370/242, 370/282
• US Class Current: 714/52
• CPC Class Codes: H04L 12/4013 Management of data rate on the bus systems modifying transmission characteristics according to link quality H04L1/0001
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

A system and method for verifying integrity of data signals communicated from a data transmit device to a receive device over a communications channel of limited bandwidth. The method comprising steps of: a) detecting instances of idle data transmit activity at the transmit device; b) accumulating data integrity information for data transmitted over the communication channel between detected idle transmit instances, the accumulating being performed by data integrity verifier devices at both transmit and receive devices; c) communicating accumulated data integrity information for data transmitted since a last detected idle data transmit instance during a current detected idle data transmit instance; and, d) verifying accumulated data integrity information communicated over the channel at the receiver device. The system and method of the invention may be used to provide intermediate data integrity checks when communication of packets belonging to a stream is interrupted without compromising bandwidth utilization. Moreover, the system and method of the invention may be used to provide data integrity verification for data communicated over two or more communications channels between instances of detected idle transmit states.

Claims

1. A system for verifying data integrity of data signals communicated between a transmitter device and a receiver device over a communications channel of limited bandwidth, said system comprising:

a control means at said transmitter device and receiver device for controlling respective data transmit and data receipt operations over said channel, said control means at said transmitter capable of detecting instances of idle data transmit activity at said transmitter;

a data integrity verifier means at said transmitter device and receiver device for verifying integrity of data communicated over said channel in between instances of idle data transmit activity,

wherein data integrity information accumulated at said transmitter since a last detected idle data transmit instance is communicated over said channel for receipt by said receiver device for data integrity verification during a current time interval of idle data transmit activity, thereby optimizing bandwidth utilization of said channel.

2. The system for verifying data integrity as claimed in claim 1, wherein said data integrity verifier means at said transmitter device and receiver device enables respective accumulation of data integrity information for data transmitted and received over said channel in between each detected idle data transmit instance, a new data integrity verification cycle being initiated for new data transmitted after each detected idle data transmit instance.

3. The system for verifying data integrity as claimed in claim 2, wherein said communications channel is a parallel bus for communicating valid data packets according to a communications protocol in between instances of idle data transmit activity.

4. The system for verifying data integrity as claimed in claim 2, wherein said communications channel for communicating data between a transmitter device and a receiver device includes a communication link for communicating sideband signals unrelated to valid data transmitted over said channel, said data integrity verifier means performing data integrity operations for both valid data packets and data transmitted as sideband signals in between instances of detected idle data transmit instances.

5. The system for verifying data integrity as claimed in claim 4, wherein said sideband signals include signals unrelated to data for controlling communication activity over said link between detected idle data transmit intervals.

6. The system for verifying data integrity as claimed in claim 1, wherein said control means at said transmitter device comprises:

means for notifying said receiver device of a detected idle data transmit instance, said control means at said receiver device responsive to said notification for initiating data integrity verification for data received from said transmitter since said prior detected idle instance.

7. The system for verifying data integrity as claimed in claim 6, wherein said means for notifying generates an IDLE tag signal in response to detecting a time interval of idle data transmit activity at said transmitter and communicating said IDLE tag signal to receiver device, said means at said receiver device responsive to said received IDLE tag signal.

8. The system for verifying data integrity as claimed in claim 6, wherein said receiver device further comprises:

a compare means for comparing accumulated data integrity information obtained from said data integrity verifier means at said receiver since a last detected idle data transmit instance with the data integrity information received from the transmitter during the current time interval of idle data transmit activity.

9. The system for verifying data integrity as claimed in claim 8, wherein said receiver device further includes means responsive to said compare means for generating an error signal when accumulated data integrity information obtained from said data integrity verifier means at said receiver device does not match the data integrity information received from the transmitter during the current time interval of idle data transmit activity.

10. The system for verifying data integrity as claimed in claim 7, wherein said generated IDLE tag signal is communicated to said receiver device over a separate communication signal line separate from said channel.

11. The system for verifying data integrity as claimed in claim 7, wherein data packets of a data stream type are interrupted by a detected idle data transmit instance, said idle cycle data transmit instance enabling data verification integrity for said stream for data communicated prior to and after said idle cycle data transmit instance, said system enabling an intermediate data integrity check.

12. The system for verifying data integrity as claimed in claim 2, wherein said data integrity verifier means includes a cyclic redundancy code (CRC) generator.

13. A method for verifying integrity of data signals communicated from a data transmit device to a receive device over a communications channel of limited bandwidth, the data transmit and data receive devices including control means for controlling respective data transmit and data receipt operations at respective transmit and receive devices, said method comprising:

a) detecting time instances of idle data transmit activity at said transmit device;

a) accumulating data integrity information for data transmitted over said communication channel between detected idle transmit instances, said accumulating being performed by data integrity verifier devices at both transmit and receive devices;

c) communicating accumulated data integrity information for data transmitted since a last detected idle data transmit instance during a current detected idle data transmit instance; and

,

d) verifying accumulated data integrity information communicated over said channel at said receiver device.

14. The method for verifying data integrity as claimed in claim 13, wherein said accumulated data integrity information is communicated to said receiver device over one of:

a serial bus or a parallel bus.

15. The method for verifying data integrity as claimed in claim 13, wherein after step c) of communicating accumulated data integrity information for data transmitted since a prior detected idle data transmit instance, a step of:

initiating a new data integrity verification cycle for new data transmitted from said transmit device to said receive device after each detected idle data transmit instance.

16. The method for verifying data integrity as claimed in claim 13, wherein step c) of communicating includes the step of notifying said receiver device of a detected idle data transmit instance, said control means at said receiver device responsive to said notification for initiating data integrity verification for data received from said transmitter since said prior detected idle data transmit instance.

17. The method for verifying data integrity as claimed in claim 16, wherein said notifying step includes generating an IDLE tag signal in response to detecting a time interval of idle data transmit activity at said transmitter and communicating said IDLE tag signal to receiver device, said receiver device responsive to said received IDLE tag signal.

18. The method for verifying data integrity as claimed in claim 16, wherein said verifying step d) includes a step of:

comparing accumulated data integrity information obtained from said data integrity verifier device at said receiver since a last detected idle data transmit instance with the data integrity information received from the transmitter during a current time interval of idle data transmit activity.

19. The method for verifying data integrity as claimed in claim 18, wherein as a result of said comparing a step of:

generating an error signal when accumulated data integrity information obtained from said data integrity verifier device at said receiver device does not match the data integrity information received from the transmitter.

20. The method for verifying data integrity as claimed in claim 17, wherein said generated IDLE tag signal is communicated to said receiver device over a separate communication signal line separate from said channel.

21. The method for verifying data integrity as claimed in claim 18, further including a step of interrupting flow of data packets of a data stream type by detecting an idle data transmit instance, said method including performing an intermediate data integrity check by enabling data verification integrity for said stream for data communicated prior to and after said detected idle data transmit instance.

22. The method for verifying data integrity as claimed in claim 15, wherein said communications channel for communicating data between a transmitter device and a receiver device includes a communication link for communicating sideband signals unrelated to valid data transmitted over said channel, wherein said accumulating, communicating and verifying steps are performed for both valid data packets and data transmitted as sideband signals in between instances of detected idle data transmit instances.

23. A system for verifying integrity of data signals communicated between a data transmit device and a data receive device in a communications network, said system comprising:

a first communication channel for communicating signals of first data content between said data transmit device and a data receive device, and a second communication channel for communicating data of second data content between said data transmit device and data receive devices;

a control means at said transmitter device and receiver device for controlling respective data signal transmit and receive operations over said first and second communications channels, said control means at said transmitter capable of detecting idle data transmit states over said first communication channel;

a data integrity verifier means at said transmitter device and receiver device for verifying integrity of said first data and second data content communicated as signals over respective said first and second channels in between instances of detected idle data transmit states,

wherein data integrity information for transmitted first data and second data accumulated at said transmitter since a last detected idle data transmit state is communicated over one of said channels for receipt by said receiver device for data integrity verification in response to detection of a current idle data transmit state, thereby optimizing bandwidth utilization of said channel.

24. The system for verifying data integrity as claimed in claim 23, further including means for notifying said receiver device of a detected idle data transmit state, said control means at said receiver device responsive to said notification for initiating data integrity verification for first and second data received from said transmitter since said prior detected idle data transmit state.

25. The system for verifying data integrity as claimed in claim 24, wherein said notifying means generates an IDLE state signal for notifying said receiver device of a detected idle data transmit state, said generated IDLE state signal being communicated to said receiver device over one of:

said first or second communications channels or, a separate communication signal line.

26. A method for verifying integrity of data signals communicated between a data transmit device and a data receive device in a communications network, said network including a first communication channel for communicating signals of first data content between said data transmit device and a data receive device, and a second communication channel for communicating second data content between said data transmit device and data receive devices, and including a means controlling respective data signal transmit and receive operations over said first and second communications channels, said method comprising the steps of:

a) detecting idle data transmit states over said first communication channel at said transmit device;

a) accumulating data integrity information for said first and second data content transmitted over respective said first and second communication channels between detected idle transmit instances, said accumulating being performed by data integrity verifier devices at both transmit and receive devices;

c) communicating over said first communication channel said data integrity information for said first and second data content transmitted over respective said first and second communication channels since a last detected idle data transmit instance; and

,

d) verifying accumulated data integrity information communicated over said channel at said receiver device.