Read Chapter 7 in your text and lesson 7 on this web site.  Then, complete this hw7. Work to understand all problems even though all problems may not be assigned.

1. Define the following terms using your own words and complete sentences.  Don't just write the acronym.

a) window
b) Frame check sequence
c) ACK
d) REJ
e) CRC
f) Error Control
g) Flow Control
h) Frame Synchronization

2. Explain how Stop and Wait flow control works together with Stop and Wait error control to manage data transmission on a data link layer connection.

3. What advantages does Go-back-N ARQ have over Stop and Wait ARQ?

4. For a transmission system:

    a. How large would the window be for a system that uses
    16-bit sequence numbers?

    b. If each frame were 150 bytes long, how many bits of data could
    be sent before the transmitter exhausted its window?

5. Describe the initialization procedure for HDLC.

6. What is the purpose of a time out?

7. Bit stuff the following HDLC frame.  The frame is organized by fields in a vertical format.  Remember, you stuff all fields except the start and end flag fields.

01111110  starting flag
11111111
01010100
11111001
11111000
00101100
11101111
11111000
00101101
11010010
01111110  ending flag

8. Explain the difference between error correction and error detection.

9. Under what circumstances would you want to use larger sequence numbers?

10. For a 10 Mbps data link using 12,000 bit frames, and assuming that electrical signals propagate at 2.5 x 10⁸ m/s:

    a. How long does it take to introduce a single frame onto the link?

    b. How long does it take for the trailing edge of the frame to travel 1,620 km?

    c. What is the total transmission time of this frame, from start to finish?

    d. If an ACK is only 6 bytes long, what is the total round trip time, from start
    of frame transmission until the ACK for that frame is received?

Used with permission of the Author; Copyright (C) Kevin A. Shaffer 1998 - 2018, all rights reserved.