Question

1. (1 pt) Under what conditions would an open-loop protocol such as an error-correcting Hamming code be preferable to the feedback type protocols discussed in Chapter 3? 2. (1 pt) Suppose that a stop-and-wait protocol was used on a channel has a 300 millisecond propagation delay and sender frames sizes of 100 milliseconds. The receiver must fully receive the frame before sending an acknowledgment. The size of the acknowledgment can be ignored. What is the channel utilization? 3. (1 pt) A channel has a propagation delay of 1 second. The receiver must fully receive the frame before sending an acknowledgment. The size of the acknowledgment can be ignored. For what range of frame sizes (in seconds) does stop-and-wait utilize at least 70% of the channel? 4. (4 pt) Using the below diagram, starting at 1 for each list the sender and receiver state numbers that would be entered given that: * the sender sends two frames, http:lpages. lu.edu/-fdoyle/b438/html/ex 42 018.htm Page 1 of 2 Exercise 4 10/7/18, 6:09 PM * the first is acknowledged successfully, * the acknowledgment to the second frame is lost. Start Start frame no fram get packet1 send frame put packet receive frame2 frame send frame wait no frame Sender Receiver

Answer 1