Monthly Archives: February 2014

Checksum

A checksum is a count of the number of bits in a transmission unit that is included with the unit so that the receiver can check to see whether the same number of bits arrived. If the counts match, it’s assumed that the complete transmission was received. Both TCP and UDP communication layers provide a checksum count and verification as one of their services.

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Cyclic Redundancy check

is an error-detecting code that is commonly used in digital networks and storage devices, to detect accidental changes in raw data.Blocks of data entering these systems get a short check value attached, based on the remainder of a polynomial division of their contents; on retrieval the calculation is repeated, and corrective action can be taken against presumed data corruption if the check values do not match.

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Parity check

A parity check is the process that ensures accurate data transmission between nodes during communication. A parity bit is appended to the original data bits to create an even or odd bit number; the number of bits with value one. The source then transmits this data via a link, and bits are checked and verified at the destination. Data is considered accurate if the number of bits (even or odd) matches the number transmitted from the source.

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Echo check

a quality check and error control technique for data that is transferred over a computer network, in which the data received is stored and also transmitted back to its origin to be compared with the original data 

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LAN and WAN

LAN stands for local area network

WAN stands for wide area network

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Simplex,Duplex and half Duplex

Simplex is when data is sent in one direction 

Duplex is when data is sent in two directions but only one way at a time.

Half Duplex is when data travels in two directions simultaneously. 

 

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Parallel data transmission

Parallel data transmission occurs when several bits of a data item are transmitted simultaneously each along its own separate channel. If a data item is represented by seven bits, there must be seven distinct channels between the sender and receiver.

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