Errors and Error Correcting CodesWhen bits are transmitted over the computer network, they are subject to get corrupted due to interference and network problems. The corrupted bits leads to spurious data being received by the receiver and are called errors.Error-correcting codes (ECC) are a sequence of numbers generated by specific algorithms for detecting and removing errors in data that has been transmitted over noisy channels. Error correcting codes ascertain the exact number of bits that has been corrupted and the location of the corrupted bits, within the limitations in algorithm.ECCs can be broadly categorized into two types −Block codes − ... Read More

Forward error correction (FEC) is an error correction technique to detect and correct a limited number of errors in transmitted data without the need for retransmission.In this method, the sender sends a redundant error-correcting code along with the data frame. The receiver performs necessary checks based upon the additional redundant bits. If it finds that the data is free from errors, it executes error-correcting code that generates the actual frame. It then removes the redundant bits before passing the message to the upper layers.Advantages and DisadvantagesBecause FEC does not require handshaking between the source and the destination, it can be ... Read More

Data-link layer uses error control techniques to ensure that frames, i.e. bit streams of data, are transmitted from the source to the destination with a certain extent of accuracy.ErrorsWhen bits are transmitted over the computer network, they are subject to get corrupted due to interference and network problems. The corrupted bits leads to spurious data being received by the destination and are called errors.Types of ErrorsErrors can be of three types, namely single bit errors, multiple bit errors, and burst errors.Single bit error − In the received frame, only one bit has been corrupted, i.e. either changed from 0 to ... Read More

Flow control is a technique that allows two stations working at different speeds to communicate with each other. It is a set of measures taken to regulate the amount of data that a sender sends so that a fast sender does not overwhelm a slow receiver.In data link layer, the sender continues to send frames only after it has received acknowledgments from the user for the previous frames. This is called feedback based flow control. Here, a restriction is imposed on the number of frames the sender can send before it waits for an acknowledgment from the receiver.Feedback based Flow ... Read More

High-level Data Link Control (HDLC) is a group of communication protocols of the data link layer for transmitting data between network points or nodes. Since it is a data link protocol, data is organized into frames. A frame is transmitted via the network to the destination that verifies its successful arrival. It is a bit - oriented protocol that is applicable for both point - to - point and multipoint communications.Transfer ModesHDLC supports two types of transfer modes, normal response mode and asynchronous balanced mode.Normal Response Mode (NRM) − Here, two types of stations are there, a primary station that ... Read More

Framing is a Data Link layer function whereby the packets from the Network Layer are encapsulated into frames. The data frames can be of fixed length or variable length. In variable - length framing, the size of each frame to be transmitted may be different. So, a pattern of bits is used as a delimiter to mark the end of one frame and the beginning of the next frame.The two types of variable - sized framing are −Character-oriented framingBit - oriented framingCharacter - Oriented FramingIn character - oriented framing, data is transmitted as a sequence of bytes, from an 8-bit ... Read More

The differences between byte stuffing and bit stuffing can be done under the following heads −What are byte stuffing and bit stuffing?Byte stuffing is a mechanism to convert a message formed of a sequence of bytes that may contain reserved values such as frame delimiter, into another byte sequence that does not contain the reserved values.Bit stuffing is the mechanism of inserting one or more non-information bits into a message to be transmitted, to break up the message sequence, for synchronization purpose.Purposes of byte stuffing and bit stuffingIn Data Link layer, the stream of bits from physical layer are divided ... Read More

DefinitionBit stuffing is the mechanism of inserting one or more non-information bits into a message to be transmitted, to break up the message sequence, for synchronization purpose.Purpose of Bit StuffingIn Data Link layer, the stream of bits from the physical layer is divided into data frames. The data frames can be of fixed length or variable length. In variable - length framing, the size of each frame to be transmitted may be different. So, a pattern of bits is used as a delimiter to mark the end of one frame and the beginning of the next frame. However, if the ... Read More

Binary is the simplest kind of number system that uses only two digits of 0 and 1 (i.e. value of base 2). Since digital electronics have only these two states (either 0 or 1), so binary number is most preferred in modern computer engineer, networking and communication specialists, and other professionals.Whereas Hexadecimal number is one of the number systems which has value is 16 and it has only 16 symbols − 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and A, B, C, D, E, F. Where A, B, C, D, E and F are single bit representations ... Read More

Whereas Hexadecimal number is one of the number systems which has value is 16 and it has only 16 symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and A, B, C, D, E, F. Where A, B, C, D, E and F are single bit representations of decimal value 10, 11, 12, 13, 14 and 15 respectively. Whereas Decimal system is most familiar number system to the general public. It is base 10 which has only 10 symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.Conversion from Hexadecimal to Decimal number systemThere are various ... Read More