Error Detection

Introduction

When it comes to networking, Error Detection is defined as the approach used to discover noise or other disablements that occur in data when it is transferred from a source to a destination. The error can be explained as a situation in which the content sent by the transmitter is different from the one received at the destination end. This feature of error detection makes sure that the transfer of data across networks is dependable. It prompts the undetected error probability, which is defined as the probability of a wrong frame being transmitted from the source to the destination. 

Error detection and correction in computer networks

As we read in the introduction, an error may occur when the data transferred from a source does not match the data received by the destination end. A few of the factors that may contribute to the addition of these errors are cross-talk and noise. The presence of error detection and correction in computer networks is to ensure an accurate transfer of data from the sender to the receiver. Error detection and correction have their own features and workings, but the process of correction of an error could be more difficult than the detection of the error.

Error Detection Techniques

A few of the key error detection techniques include:

1. Checksum.
2. Simple parity check.
3. Two-dimensional parity check.
4. Cyclic redundancy check.

Checksum

This method of error detection is based on the ideology of redundancy.

In this error detection method:

1. The data that has to be transmitted is split into k parts, which are m bits each.
2. The segments are then computed by using 1’s complement arithmetic for acquiring the sum.
3. Along with the data portion mentioned above, the segment of checksum is sent to the receiver.
4. The obtained segment of data and checksum is added using 1’s complement arithmetic for acquiring the sum, after which the sum is complemented.
5. The data obtained at the receiver’s end is accepted if the result is found to be zero. Otherwise, it is discarded.

Simple parity check

In this error detection method, from the origin, blocks of data are put through a parity bit generator form. In this form, the following process is undergone:

1. With the presence of an odd number of 1’s, one is computed to the block.
2. With the presence of an even number of 1’s. 0 is computed.

This process got the name of even parity checking from its process of making the total count of 1’s in the scheme even.

Two-dimensional parity check

This error detection method arranged the information in a tabular form.

1. For each of the rows, the parity check bits are calculated, which is identical to single-parity checks.
2. A portion of bits in this method is split into rows. Then, to a block, the redundant row of the bits is computed.
3. In the destination end, there is a comparison of the parity bits to the ones calculated from the data received.

Cyclic redundancy check (CRC)

This method of error detection is built on binary division.

1. A sequence of cyclic redundancy bits is attached at the end of the data unit to ensure that the proceeding data unit is divisible by a second.
2. At the receiver’s end, the data accumulated is divided by the digit mentioned earlier. 
3. After the division, if there is no remainder, the data is accepted as accurate.
4. If a remainder is present after division, it implies possible damage which has to be discarded.

Error detection in English

Error detection in English is a part of reading comprehension. In the sentence correction section of a paper, the topic of error detection in English is included. In this, the prime objective is to find whether a sentence has an error and needs to be rectified or not. There could be an error in any of the following portions of the sentence – grammar, verb, structure, articles, tenses, punctuation, or modals. In order to be able to omit errors in a sentence, an individual needs to have a good command of the language, mainly the grammar portion and the vocabulary.

Conclusion

In this article, we read and understood in detail the meaning of error detection and correction. Along with a specific understanding of the topic, we went through the different types of error detection techniques known as – checksum, simple parity check, two-dimensional parity check, and cyclic redundancy check. Each of the techniques mentioned was explained in detail in the article. Furthermore, the above-written article includes – what is error detection in English, what adds to it as errors in English, and how errors are omitted in a sentence.