1. What is the checksum of following data word
2,4,5,7,9
- A. 5
- B. 3
- C. -27
- D. 27
- E. None of the above
Ans- B. 3
Solution:- In Data Link layer detecting of error is is done by using Checksum
In above example given data words are 2,4,5,7,9
Now convert all these data words in binary string we get 0010,0100,0101,0111,1001
now add all these data string than we get 27 which conversion in binary is 11011
all data words are in 4 digit but 27 is in 5 digit now we convert 27 into 4 digit binary code
we have to add left significant bit to rest of the bit
now we send these datagram with checksum 3 as 2,4,5,7,9,3
At Receiver side again we add all these datagrams and get 30
now convert this 30 into binary number 11110
again we add left most bit to remaining bit
