Testbook test series

Question

a bit stuffing based framing protocol uses an 8bit delimiter pattern of HDLC's flag .if the input bit string is 1011111110111110,then the output bit string after after stuffing is 

 

Comments

The 8-bit delimiter pattern is 01111110

While sending data, to avoid getting it confused with delimiter pattern, a 0 is stuffed by sender when 5 consecutive 1's are encountered in data.

Receiver ignores the 0 after 5 1's while parsing data.

Hence the answer.

Answer 1

Hdlc uses 7E (01111110) as a delimiter pattern. So to encode 1011111110111110 it will add a 0 after every 5 ones.

So answer is 1011111'0'11011111'0'0

Here '0' is the stuffed bit.

Comments

you said that  hdlc use 7E delimiter , you have studied it or there is a method to find delimiter pattern

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Its a standard.

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is it rule adding 0 after every occurrences of 1s.

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yes