Error detection and correction

1. Class Note
On
Error Detection and correction
Course Title: Data Communication
Course code: CSE 313
Submitted To
Pranab Bandhu Nath
Senior Lecturer
Department of CSE
City University
Submitted By
Somaya Akter
ID: 1834902142
Batch:49th
(B)
Department of CSE
City University
Submission date:17.10.2021

2. Errors
When bits are transmitted over the computer network, they are subject to get corrupted due to
interference and network problems. The corrupted bits lead to spurious data being received by
the destination and are called errors.
Types of Errors
Errors can be of three types
Single bit error − In the received frame, only one bit has been corrupted, i.e. either changed
from 0 to 1 or from 1 to 0.
Multiple bits error − In the received frame, more than one bits are corrupted.
Single bit error
Multiple bit
error
Burst Error
Errors

3. Burst error − In the received frame, more than one consecutive bits are corrupted.
Error Detection and correction (Implemented either at Data link layer or Transport Layer of OSI
Model)
Whenever a message is transmitted, it may get scrambled by noise or data may get corrupted. To
avoid this, we use error-detecting codes which are additional data added to a given digital
message to help us detect if any error has occurred during transmission of the message.
Basic concepts
• Networks must be able to transfer data from one device to another device with complete
accuracy.
• Data can be corrupted during transmission.
• For reliable communication, error must be detected and corrected.

4. Error detection means to decide whether the received data is correct or not without having a copy
of the original message. Error detection uses the concept of redundancy, which means adding
extra bits for detecting errors at the destination.
Redundancy
The central concept in detecting or correcting errors is redundancy. To be able to detect or
correct errors, we need to send some extra bits with our data. These redundant bits are added by
the sender and removed by the receiver. Their presence allows the receiver to detect or correct
corrupted bits.
Error detection uses the concept of redundancy, which means adding extra bits for detecting
errors at the destination. These redundant bits are added by the sender and removed by the
receiver. Their presence allows the receiver to detect or correct corrupted bits.

5. https://www.tutorialspoint.com/error-detection-and-correction-in-data-link-layer
Chapter 9 Error Detection and Correction
Data Communications and Networking by Behrouz A.Forouzan.pdf
https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.slideserve.com%2Fraheem%2Fchapter-10-
error-detection-and-correction&psig=AOvVaw3nuKa0zcKCx_A-
n7FX4om8&ust=1634627875718000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCMCw-
cK10_MCFQAAAAAdAAAAABAD
http://www.eee.iub.edu.bd/CourseMaterials/ETE%20304/Lec7B%20Error%20Detection%20and%20Corre
ction.pdf