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TMS570LS3137: About Transmission Redundancy

user4777395
Intellectual 480 points

CAN 9 Transmission Redundancy
ETH 9 Transmission Redundancy

Is this saying to find the garbled data by sending the same data several times?

Is the target to be found different from CRC of CAN or check sum of UDP?

  • 0
    TI__Guru 59540 points
    "Transmission Redundancy" actually has a formal meaning as defined within the functional safety standards (IEC61508 and ISO26262) even if it is not specific to CAN or Ethernet protocols. The definition given in the standard is "The information is transferred several times in sequence. The repetition is effective only against transient failures."

    This measure would be in addition to the CAN CRC in message or the Ethernet checksum in UDP. This would potentially help discover errors if , perhaps, the CRC comparison mechanism or the UDP Checksum checking mechanism falsely returned a pass (transient or permanent error) and allowed acceptance of the message erroneously. Since this involves transmissions from outside devices, this mechanism would have to be implemented on a system level within the application and may not always be achievable given application level constraints.
  • 0 in reply to Chuck Davenport
    Intellectual 480 points

    Does this match recognition that incorporates a checksum or increment counter in the transmission data in order to find an error in the application?

  • 0 in reply to user4777395
    TI__Guru 59540 points

    user4777395 said:
    Does this match recognition that incorporates a checksum or increment counter in the transmission data in order to find an error in the application?

    No. The type of approach you are describing would be considered information redundancy. Transmission redundancy means the actual duplicate transmission of the data or message packet so the second set of received data can be compared to the first. This protects against transient faults impacting the transmission of the data. Note that it may not be necessary to use this mechanism if you have other protections in place such as information redundancy, in message CRC, bit error detection, etc that can detect corruption within the message. The impact of including or excluding such a diagnostic measure is dependent on the application needs and would need to be evaluated through fault tree analysis in combination with your overall system Safety Requirements Specification (SRS).