Cyclic Redundancy Check in Computers Network
- 1. Maharshi Dayanand Saraswati University Presentation Topic: Cyclic Redundancy Check Subject : Computer Networks Class: MCA1 Presented by : Shivangi Tak Submitted to: Praful Sir
- 2. Welcome To My Presentation Topic : Cyclic Redundancy Check
- 3. 03 01 02 04 Agenda Error Detection Method Cyclic Redundancy Check Performance of CRC Advantages of CRC
- 4. What is Error Detection ? Networks must be able to transfer data from one device to another with complete accuracy. Data can be corrupted during transmission. For reliable communication, errors must be detected and corrected.
- 6. Cyclic Redundancy Check CRC or Cyclic Redundancy Check is a method of detecting errors in the communication channel. CRC uses Generator Polynomial which is available on both sender and receiver side.
- 7. CRC Generation At Sender Side 1.Find the Length of Divisor ‘L’ 2.Append 0 ‘L-1’bits to the original bits 3.Perform Binary Digit Operation 4.Remainder of the division=CRC A B A XOR B 0 0 0 0 1 1 1 0 1 1 1 0
- 8. A B A XOR B 0 0 0 0 1 1 1 0 1 1 1 0 1 Find the Length of Divisor ‘L’ 2 Append 0 ‘L-1’bits to the original bits 3 Perform Binary Digit Operation 4 Remainder of the division=CRC Finally, Cyclic Redundancy check will be generated as shown.
- 9. The sender performs a division operation on the bits being sent and calculates the remainder. Before sending the actual bits, the sender adds the remainder at the end of the actual bits. (Data Bits+ Remainder)
- 10. Receiver Side: Code word received at the receiver side 100100001 (data + CRC)
- 11. At The Receiver Side Receiver divides received data (data + CRC) with generator. If remainder is zero, data is correctly received. Else, there is error.
- 12. A B A XOR B 0 0 0 0 1 1 1 0 1 1 1 0 Therefore, the remainder is all zeros. Hence, the data received has no error.
- 13. Advantages of CRC 1. Cyclic codes have a very good performance in detecting single-bit errors, double errors, an odd number of errors. 2. They can easily be implemented in hardware and software. 3. They are especially fast when implemented in hardware. 4. This has made cyclic codes a good candidate for many networks.
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