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

The given transmitted message 1001 1100 0101 1100. The checksum is used to detect errors caused by message transmission. The message has 4-bit word size. To calculate checksum we add the message word

first two message 1001 + 1100 = 10101 (1 is carry)

add the carry 0001 + 0101 = 0110

add the result with third message 0110 + 0101 =1011

add result with fourth 1011 + 1100 = 10111

add the carry 0111 + 0001 = 1000

take one\'s complement of final result = 0111

checksum for the message = 0111