Question
Consider the previous problem, but instead suppose these 10 bytes contain
a. the binary representation of the numbers 1 through 10.
b. the ASCII representation of the letters B through K (uppercase).
c. the ASCII representation of the letters b through k (lowercase).
Compute the Internet checksum for this data.
Answer
The following steps are used to calculate the the Internet checksum for this data:
- Take 16- bits integers and perform addition operation in setp 1.
- Next, convert 1’s complement of final sum value in step 2.
- This is final binary value is called the Internet checksum.
a)
The binary representation of the numbers 1 through 10:
| Numbers | Binary |
| 1 | 00000001 |
| 2 | 00000010 |
| 3 | 00000011 |
| 4 | 00000100 |
| 5 | 00000101 |
| 6 | 00000110 |
| 7 | 00000111 |
| 8 | 00001000 |
| 9 | 00001001 |
| 10 | 00001010 |
Now, calculate the Checksum by using above step 1 and step 2:
setp 1:
- In above table contains 10 binary digits. Thuse divide five 16-bit integers categories and add it.
So, sum is 0001 1001 0001 1110
setp 2: Now, convert 1's complement for check sum result. 1's complement means convert 0's to 1's and 1's t0 0's.
0001 1001 0001 1110=>1110 0110 1110 0001
So, the Internet checksum for the binary representation of the numbers 1 through 10 is 1110 0110 1110 0001
b)
The ASCII representation of the letters B through K (uppercase) :
| Letters | ASCII |
| B | 66 |
| C | 67 |
| D | 68 |
| E | 69 |
| F | 70 |
| G | 71 |
| H | 72 |
| I | 73 |
| J | 74 |
| K | 75 |
Now, convert ASCII values to binary representation:
| ASCII Value | Binary |
| 66 | 01000010 |
| 67 | 01000011 |
| 68 | 01000100 |
| 69 | 01000101 |
| 70 | 01000110 |
| 71 | 01000111 |
| 72 | 01001000 |
| 73 | 01001001 |
| 74 | 01001010 |
| 75 | 01001011 |
Now calculate the checksum by using above step 1 and step2:
setp 1:
- In above table contains 10 binary digits. Thuse divide five 16-bit integers categories and add it.
The sum is =01011111 01100011
setp 2: Now, convert 1's complement for check sum result. 1's complement means convert 0's to 1's and 1's t0 0's.
So, the Internet checksum for the ASCII representation of the letters B through K (uppercase) is 10100000 10011100
c)
The ASCII representation of the letters b through k (lowercase):
| Letters | ASCII |
| a | 98 |
| b | 99 |
| c | 100 |
| d | 101 |
| e | 102 |
| f | 103 |
| g | 104 |
| h | 105 |
| i | 106 |
| j | 107 |
Now, convert ASCII values to binary representation:
| ASCII Value | Binary |
| 98 | 01100010 |
| 99 | 01100011 |
| 100 | 01100100 |
| 101 | 01100101 |
| 102 | 01100110 |
| 103 | 01100111 |
| 104 | 01101000 |
| 105 | 01101001 |
| 106 | 01101010 |
| 107 | 01101011 |
Now calculate the checksum by using above step 1 and step2:
setp 1:
- In above table contains 10 binary digits. Thuse divide five 16-bit integers categories and add it.
The sum is 11111111 11111011
setp 2: Now, convert 1's complement for check sum result. 1's complement means convert 0's to 1's and 1's t0 0's.
So, the Internet checksum for the ASCII representation of the letters b through k (lowercase) is 00000000 00000100