Ben Miller
CS61 - Networks and Networking
HW 4 - Chapter 7 (Do 7.1, 7.2, 7.3 or 7.6, 7.7, 7.26)


7.1
a) Increasing the message size would be beneficial because it means that less messages would
need to be passed back and forth.  Since this is a point-to-point link there is only two machines
communicating on the link at one time.  The more of the message that can be sent at one time
also means less acknowledgements that need to be passed back to the transmitter.






b) Increase the number of frames sent will increase the number of times the line will need to be
used by these machines.  The is not good use of the line since these are the only two machines
using this line.  It would be more efficient to send as much of the message as possible at one
time.






c) Increasing the frame size will decrease the efficiency of the line utilization.  The larger
the frame, the more of the line is taken up by that frame so that no other message can be sent
across the line.  This might not matter though since this is a point to point link used only
by these two machines communicating.






7.2






7.6
I am assuming that the author is contrasting this with just sending the parity bit at the end of
the entire message.  The more often that a parity bit is placed in the message the more likely
you will have a chance to detect an error.  In other words, the probability will decrease the
more often that a parity bit is placed in the message.  So if a parity bit is placed after each
character then one could check each character to see if an error occurred.