### Computing an Internet checksum

Consider the two 16-bit words (shown in binary) below. Recall that to compute the Internet checksum of a set of 16-bit words, we compute the one's complement sum [1] of the two words. That is, we add the two numbers together, making sure that any carry into the 17th bit of this initial sum is added back into the 1's place of the resulting sum); we then take the one's complement of the result. Compute the Internet checksum value for these two 16-bit words:

11110101 10101100

*this binary number is 62892 decimal (base 10)*

11010100 01111000

*this binary number is 54392 decimal (base 10)*

### Question List

1. What is the sum of these two 16 bit numbers? Don't put any spaces in your answer

2. Using the sum from question 1, what is the checksum? Don't put any spaces in your answer

### Solution

1. The sum of 11110101 10101100 and 11010100 01111000 = 11001010 00100101

2. The internet checksum is the one's complement of the sum: 11001010 00100101 = 00110101 11011010

That's incorrect

That's correct

The answer was: 11001010 00100101

The answer was: 00110101 11011010