CRC cyclic redundancy check baisc demo.pptx

cyclic redundancy check

1. Cyclic Redundancy Check (CRC) Data Link Layer Overview and Working Mechanism

2. Introduction • Error detection is essential in data communication. • Cyclic Redundancy Check (CRC) is a widely used technique. • Operates at the Data Link Layer of the OSI model. • Detects accidental changes to raw data during transmission.

3. Basic Concept of CRC • Treats data as a binary number. • Divides data by a predetermined polynomial. • Remainder from division is the CRC value. • CRC is appended to the frame before transmission.

4. Working Mechanism 1. Sender encodes data with CRC value. 2. Receiver divides received data by same polynomial. 3. If remainder = 0 → No error detected. 4. If remainder ≠ 0 → Error detected.

5. Example of CRC • Data: 1101011011 • Polynomial: 10011 • Division gives remainder. • Remainder appended as CRC bits. • Receiver checks using same polynomial.

6. Advantages of CRC • High error detection capability. • Simple implementation in hardware. • Detects burst errors effectively. • Widely adopted in Ethernet, storage devices, etc.

7. Limitations of CRC • Cannot correct errors (only detection). • Ineffective against intentional data modification. • Computational overhead for large data. • Not suitable for cryptographic integrity.

8. Conclusion • CRC is essential for reliable communication. • Provides strong error detection at the Data Link Layer. • Balances efficiency and robustness. • Used extensively in networking and storage systems.