The Spark

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The Spark

  1. 1. EKTA M.S.SUPRIYA MALINI.B.S MANASA.R GOWRI.P
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  3. 3. <ul><li>Error detection and correction </li></ul><ul><li>Understanding Checksum </li></ul><ul><li>Different algorithms of checksum </li></ul><ul><li>Implementation of checksums </li></ul><ul><li>Applications </li></ul><ul><li>Advantages and disadvantages </li></ul>
  4. 4. <ul><li>Error detection uses the concept of </li></ul><ul><li>redundancy, which means adding extra bits </li></ul><ul><li>for detecting errors at destination </li></ul>ERROR DETECTION
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  6. 6. <ul><li>Parity check </li></ul><ul><li>Cyclic redundancy check(CRC) </li></ul><ul><li>Checksum </li></ul>
  7. 7. <ul><li>used by the higher layer protocols </li></ul><ul><li>It is based on the concept of redundancy(VRC, LRC, CRC ….) </li></ul>
  8. 8. <ul><li>To check data integrity when data is sent through telecommunication networks such as INTERNET. </li></ul><ul><li>To check data integrity of the data stored. </li></ul><ul><li>To verify data burned to CD-ROM, CD-R, DVD, DVD-R etc… </li></ul>
  9. 9. <ul><li>Parity byte or word </li></ul><ul><li>Modular sum </li></ul><ul><li>Position dependent checksum </li></ul><ul><li>Fletcher </li></ul><ul><li>Adler </li></ul>
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  11. 11. <ul><li>The unit is divided into k sections, each of n bits. </li></ul><ul><li>All sections are added using one’s complement to get the sum. </li></ul><ul><li>The sum is complemented. </li></ul><ul><li>If the result is zero, the data are accepted: otherwise, rejected </li></ul>
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  14. 14. <ul><li>The IP checksum is the 16 bit one's complement of the one's complement sum of all 16 bit words in the header. </li></ul>
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  18. 18. <ul><li>Enhances file system integrity </li></ul><ul><li>Detection of error in large data </li></ul><ul><li>Embedded control networks </li></ul><ul><li>Antivirus checksum(winHKI) </li></ul><ul><li>Integrity protection (cryptographic checksum) </li></ul>
  19. 19. <ul><li>It is used only for error detection </li></ul><ul><li>Constraints of grammar based checksum </li></ul><ul><li>Intentional corruption goes undetected </li></ul><ul><li>Change in order of bytes goes undetected </li></ul><ul><li>It is not as strong as CRC in error checking </li></ul>
  20. 20. <ul><li>Internet application </li></ul><ul><li>Grammar based checksum </li></ul><ul><li>Bank account number </li></ul><ul><li>Social security number </li></ul><ul><li>Source code management </li></ul><ul><li>Password checking </li></ul>

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