Suppose that a message 1001 1100 0101 1100 is transmitted us

Suppose that a message 1001 1100 0101 1100 is transmitted using Internet Checksum (4-bit word). What is the value of the checksum?

Solution

In question, it mentioned 4-bit checksum, So we need to divide the message into 4 bit words and then add all.

1001 + 1100 + 1010 + 1100 = 100110 (binary addition)

We want 4-bit checksum, So bring 10 down and add

0110 + 10 = 1000 (binary addition)

And checksum will be the complement of 1000, which is 0111.