New Method in Error Detection

Size: px

Start display at page:

Download "New Method in Error Detection"

Jesse Ferguson
5 years ago
Views:

1 New Method in Error Detection Shir Mohammad tavangari Department of Computer Engineering, Babol university Abstract This article is about one of the functions of the data link layer of the network stack comes to deals. This layer is one of the most important duties to help control error detection and error correction that will focus on the detection of errors and number of errors. At the time of the proposed algorithm needs to be able to accurately and efficiently detect the error. The approach in this paper is to identify an error emphasis In this way the frame will be divided into three parts data in it and the type of work done on it is written Receiver according to which there can be right or wrong with the recognition and If an error has occurred and also specifies the number of errors.in many ways this has been published But in this article we have tried new ways And be provided with its own characteristics The performance of this method compared to other methods is also shown. Keywords: Data Link Layer, Network,Algorithm,Error Detection,Error Correction 251

2 Introduction The general idea for achieving error detection and correction is to add some Redudancy (i.e., some extra data) to a message, which receivers can use to check consistency of the delivered message, and to recover data determined to be corrupted. Error-detection and correction schemes can be either systematicor non-systematic: In a systematic scheme, the transmitter sends the original data, and attaches a fixed number of check bits (or parity data), which are derived from the data bits by some Deterministic algorithm. If only error detection is required, a receiver can simply apply the same algorithm to the received data bits and compare its output with the received check bits; if the values do not match, an error has occurred at some point during the transmission. In a system that uses a non-systematic code, the original message is transformed into an encoded message that has at least as many bits as the original message. Good error control performance requires the scheme to be selected based on the characteristics of the communication channel. Common channel model include memory-less models where errors occur randomly and with a certain probability, and dynamic models where errors occur primarily in bursts. Consequently, error-detecting and correcting codes can be generally distinguished between random-error-detecting/correcting and burst-error-detecting/correcting. Some codes can also be suitable for a mixture of random errors and burst errors. If the channel capacity cannot be determined, or is highly variable, an error-detection scheme may be combined with a system for retransmissions of erroneous data. This is known as automatic repeat request(arq), and is most notably used in the Internet. An alternate approach for error control is hybrid automatic repeat request (HARQ), which is a combination of ARQ and error-correction coding. Error detection is most commonly realized using a suitable hash function (or checksum algorithm). A hash function adds a fixed-length tag to a message, which enables receivers to verify the delivered message by recomputing the tag and comparing it with the one provided. There exists a vast variety of different hash function designs. However, some are of particularly widespread use because of either their simplicity or their suitability for detecting certain kinds of errors (e.g., the cyclic redundancy check's performance in detecting burst errors). A random-error-correcting code based on minimum distance coding can provide a strict guarantee on the number of detectable errors, but it may not protect against a preimage attack. A repetition code, described in the section below, is a special case of error-correcting code: although rather inefficient, a repetition code is suitable in some applications of error correction and detection due to its simplicity. 252

3 Repetition codes Parity bits Checksums and CRC New methods Overview in picture Step 1 Shaped fame 253

4 Main code: the main data is placed and pass receiver. Method type: method type to change the code Code change: code change and method type will be sent by the sender to the receiver. Step 2 Methods: 1-Move to Left to Right_0 or M_L_0 2-Move to Left to Right_1 or M_R_1 3-2 s Complement 1-Move to Left to Right_0 2-Move to Left to Right_1 254

5 3-2 s Complement Step 3 Output 1-Move to Left to Right_0 255

6 256

7 2-Move to Left to Right_1 257

8 3-2 s Complement 258

9 Conclusion These algorithms in terms of Speed, Performance, Simplicity and understandable are very good. References 1.William Stalling,Data And Computer communication,8 th Edition,prentice hall, James f.kurose & Keith W. Ross, Computer Networking, 5 th Edition,Pearson, Hamming, Coding And Information Theory,2 nd Ed, Prentice Hall, [Online]. Available: 5.[Online]. Available: 259

PART III. Data Link Layer MGH T MGH C I 204

PART III. Data Link Layer MGH T MGH C I 204 PART III Data Link Layer Position of the data-link layer Data link layer duties LLC and MAC sublayers IEEE standards for LANs Chapters Chapter 10 Error Detection and Correction Chapter 11 Data Link Control