- 2070 Chaitra · 5+3 marks
Error correction vs detection, bit stuffing
Short answer
Error detection only identifies errors and requests retransmission; error correction identifies and corrects errors without retransmission. For bit stuffing with flag 01111110, insert a 0 after five consecutive 1s. The transmitted string is 0111101111100111110110.
What is the difference between Error Correcting and Error Detection process? A bit string 01111011111011111110 needs to be transmitted at the data link layer. What is the string actually transmitted after bit stuffing, if the flag pattern is 01111110?
Error correction vs error detection
| Point | Error detection | Error correction |
|---|---|---|
| Purpose | Only finds whether an error has occurred | Finds and corrects the error without retransmission |
| Redundancy | Fewer redundant bits | More redundant bits |
| Method | Parity, checksum, CRC | Hamming code, convolutional codes (FEC) |
| Action after error | Discard frame and ask for retransmission (ARQ) | Receiver fixes the bits itself |
| Complexity | Simple | Complex |
| Use | Reliable links (Ethernet) | Noisy links, satellite, where retransmission is costly |
Bit stuffing numerical
Rule: with flag 01111110, insert a 0 after every five consecutive 1s of the data.
Data: 01111011111011111110 (20 bits).
original : 0 1111 0 11111 0 1111111 0
stuffed : 0 1111 0 11111[0] 0 11111[0] 11 0
| Segment | Result |
|---|---|
| 0 1111 0 | 011110 (no run of five 1s, sent unchanged) |
| 11111 0 | five 1s, so insert 0: 111110, then the original 0 |
| 1111111 0 | after five 1s insert 0: 111110, then 11, then 0 |
Stuffed bit string (22 bits): 0111101111100111110110
Transmitted frame with flags: 01111110 0111101111100111110110 01111110.
✓ Answer checked by Claude Opus 5.5 (high effort)
Related questions
- Bit stuffing of a given string (1) · Computer Networks and Security, chapter 3
- Functions of data link layer · Computer Networks and Security, chapter 3 · asked 3×
- Data link layer framing · Computer Networks and Security, chapter 3 · asked 3×
- Error detection vs correction; rate ½ convolutional encoder · Communication Systems, chapter 8
- Short note: Error detection and correction capability · Communication Systems, chapter 8
- Error detection in serial data transmission · Instrumentation II, chapter 3 · asked 2×