Error detection data communication
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This presentation introduces error detection. It defines errors as bits that are changed during transmission from source to destination. There are two types of errors: single-bit errors affecting one bit, and burst errors affecting multiple consecutive bits. Checksums are introduced as a method of error detection where a calculated value is sent with the data and re-calculated at the destination to check for errors. The contents then describe how checksums are calculated and used to detect errors.
Error detection data communication
- 2. Submitted To: NARAYAN RANJAN CHAKRABORTY DEPARTMENT OF CSE DAFFODIL INTERNATIONAL UNIVERSITY Submitted By: 1. MD MOKLASAR RAHMAN BAPPY ID: 143-15-4504 2. MOSHARRAF FAHAD ANIK ID: 171-15-9247
- 4. Contents: 1. Error 2. Error Detection 3. Types of Error 4. Check SUM
- 5. ERROR Abit error occurs when asource sendsabit, b, and thedestination receives NOT b. i.e. b b 1. The error can take place on the link , in a switch or router along the path, or in the source or destination (e.g. failed hardware, or bit errors in memories).
- 6. 1 0 0 1 1 1 0 0 1 0 1 1 0 0 1 0 1 0 0 1 0 1 Sent Received Error
- 7. Types Of ERROR • Singlebit error :- - Only one bitin the data unit haschanged. • Burst error :- - It means that two or more bits in the data unit haschanged.
- 8. Single Bit ERROR 0 0 0 0 1 0 1 0 0 0 0 0 0 0 1 0 Burst Error 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 1 0 1 0 1 1 1 0 1 0 1 0 0 0 0 1 1 Received Sent Sent Received Bits corrupted by BurstError 0changedto 1
- 9. Detecting & Correcting ERROR • When we transmit a message, we typically append a checksum to the message. • The checksum is calculated by performing a function over all thebits in the message.
- 10. Check SUM A checksum is a simple type of redundancy check that is used to detecterrors indata.
- 11. Sendersite: 1. Themessageis divided into 16-bit words. 2.Thevalue of the checksum word is set to0. 3.All words including the checksumare added using one’s complement addition. 4. Thesum is complemented and becomes the checksum. 5.Thechecksum is sent with the data.
- 13. Receiversite: 1.The message (including checksum) is divided into 16-bit words. 2.All words are added using one’scomplement addition. 3.Thesum is complemented and becomes the new checksum. 4.If the value of checksum is 0, the message is accepted; otherwise, it isrejected.
- 16. Advantage Checksummainly detects single-bit changesin data. Achecksum is mainly employed in data validation when implementing software.
- 18. Thank You Anyone have any Question ?