DATA LINK LAYER WIRED NETWORKS
DATA LINK CONTROL DLC
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Code word
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data word
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rotated word
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shifted word
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Detailed explanation-1: -Cyclic codes are special linear block codes with one extra property. In a cyclic code, if a codeword is cyclically shifted (rotated), the result is another codeword. For example, if 1011000 is a codeword and we cyclically left-shift, then 0110001 is also a codeword.
Detailed explanation-2: -CRC codes are a type of cyclic code. An end-around shift of a cyclic code word produces another valid code word. Like the Hamming codes discussed so far in this chapter, CRC codes are also linear block codes. CRC codes are typically used to detect burst errors, errors in a sequence of bits.
Detailed explanation-3: -"A linear block code is a block code in which the exclusive-or of any two codewords results in another codeword. A cyclic code is a linear block code in which the rotation of any codeword results in another codeword."