$10$ points$)$ Both TCP and UDP use $1$s complement for their checksum values:

a$.$ Suppose that you have the following $8-$bit bytes: $01010101,01110011,$ and $01001100.$ Calculate

the $1$s complement of the sum of all of these $8-$bit bytes $($that is$,$ add them all together and then

determine the $1$s complement from that sum$),$ being sure to handle the overflow as described in

the text in a circular fashion. Note that TCP and UDP use $16-$bit words in computing the

checksum, but only $8-$bits are used here for simplicity.

b$.$ Is it possible that a $1-$bit error will go undetected by the checksum? If yes, explicitly state how

this can happen. $($If you change $1$ bit of $1$st $8$ bit$)$

c$.$ Is it possible that a $2-$bit error will go undetected by the checksum? If yes, explicitly state how

this can happen. $($If you change $2$ bits$)$