Instructor :
Seung Bae Im
Closed book, closed notes. Write neatly.
Name : _____________________________
1.(28 points) Describe the following terms and
answer the questions.
(a) Discuss the
relationship between Signal’s bandwidth and a Channel’s bandwidth.
(b) What is an
SAP(Service Access Points)? Give an example.
(c)
Discuss how the bandwidth of a voice
is decided to range between 300 – 3400 Hz?
(d) State why the
OSI Model is important?
(e) Discuss the
overlap of functions between ISO and ITU-T and also discuss how they cooperate.
(f) Discuss the
role of IEEE in the arena of network standards.
(g) List the contents of RFCs, in other words, what kinds of
information is found in RFCs.
2.(6 points) State the reasons why TCP/IP protocol
suite is dominant(used almost everywhere, used on almost every machine) over all other
protocols including OSI protocols.
3.(20 points) Describe/discuss
(a) Bridges have
“closed loop problem”. Describe the problem and state how it is solved.
(b) Discuss how all
the generations of Ethernets(of different
speeds) can coexist. Include the word, “autonegotiation” in your description.
(c) Describe how the CRC code works.
(d) Discuss the significance
of the
4.(20 Points) Answer the questions.
(a)
Describe the difference between
Ethernet hubs and Ethernet switches.
(b)
What is ISM(Industrial, Scientific, Medical) band? What is the
restriction of the band?
(c) Discuss how Full duplex Ethernet is possible using Ethernet switches.
(d)
In 802.11 wireless Lans, there are
two problems; (a) Hidden station problem (b) Exposed station problem.
Describe them.
5.(10 points) Show a
diagram which illustrates how T-1 carrier multiplexes 24 digitized voices.
Also, show the calculation to derive its data rate of 1.544 Mbps. In the
calculation, clearly mark each component.
6.(16 points) Discuss/describe
(a) Draw the
protocol diagram(showing layers and sublayers) for the LAN protocols—Show at least IEEE
802.2, 802.3, 802.11. Also clearly show
the layers/sublayers on the
diagram. Also discuss why IEEE divided the Data Link layer into two sublayers.
(b)
What is “flow control”? Why do we need it?
(c)
Describe
the difference between “go-back-n ARQ” & “Selective Repeat ARQ”.