1. What does a beacon frame do? Explain.
2. What are the differences between a master device in Bluetooth, and a base station in 802.11?
3. Download RFC 5944 (https://www.rfc-editor.org/), and answer the following questions:
a. What organization did the editor of RFC 5944 work for?
b. How is that organization different from the authors of many Internet protocol RFCs, such as TCP, IP, UDP, etc.?
c. Also from that RFC, what is a "co-located care-of address"?
d. If you're using such a thing, who performs decapsulation of the datagrams?
e. How long does an extension have to be before the Long Extension Format is used?
4. Research two advanced (i.e. new, expensive) cell phones from different brands. You may need to download user manuals or find other technical documentation. For each, describe:
a. The make and model of the phone
b. What frequency band it uses
c. What type of phone standards it uses (GSM, IS-95, CDMA, etc.). [Don't tell me it uses AAC or 802.11g - those aren't phone standards!]
d. If the encoding wasn't described in the lecture, describe it briefly (what other protocols is it based on, where is it used, etc.)
e. Cite the sources used
5. When is an anchor MSC used in a GSM network?
6. What are the differences between infrastructure and ad hoc modes in 802.11?
7. Why are acknowledgments used in 802.11 but not in wired Ethernet?
8. The phone protocols UMTS and CDMA-2000 are based on what earlier standards?
9. Suppose two cell phones are in a foreign network with a foreign agent. Is it possible for both of them to have the same care-of-address in mobile IP? Explain your answer.
10. Of what does a basic service set consist?
11. Describe the hidden terminal problem in your own words.
12. Describe how and why a chipping rate is used.
13. What is the difference between CSMA and CDMA? Describe in what contexts are they used, and briefly how each works.
14. Ethernet can stop transmitting in mid-frame, while 802.11 always transmits a full frame. Why is this difference needed?
15. What are the three main functions of media players?
16. Estimate the jitter for a web site on the other side of the world.
a. Find a university really far away (Indonesia, New Zealand, South Africa, etc.). Identify the university you used.
b. Run five ‘ping' commands, and record the four RTT estimates from each command. You should have a total of 20 RTT values.
c. Enter them in Excel, and calculate their standard deviation ( =STDEV(cell range) where cell rangeis for example A1:A20).
d. Identify the site you used, show the RTT data, and give the standard deviation with correct units.
e. Describe the type of local link used (wired or wireless) and level of Internet service used (DSL, Cable, FIOS, Drexel, etc.)
f. Did you expect more or less jitter? Why?
17. Figure 7.9 (p. 620) shows an interleaved stream from an original stream of 16 characters. If the original stream was "Quieter turtles." (Notice the space and period are also characters), how would the interleaved stream read?
18. From the book Animal Farm, a famous quote is "All animals are equal, but some animals are more equal than others." Which of the packet scheduling mechanisms we looked at (FIFO, etc.) is most like this quote? Justify your answer.
19. One of the encoding methods used in the SIP discussion is μ-law (mu-law) PCM (pulse code modulation). What sampling rate and number of bits per channel are used in mu-law PCM? Where in the world is it used? Cite sources used.
20. What connection is there between the compression protocol H.264 and MPEG?
21. How does Skype choose which transport protocol to use?
22. How do changes in the sequence number in RTP differ from those in TCP?
23. Suppose in an RTP session, there are three microphones plus two video cameras (which presumably also have mics). How many SSRCs are used for this session? How could your answer change, depending on the compression protocols used for audio and video?
24. Suppose a router's queue holds 4 Mbit of data, and 12 kbit packets arrive at the router at a rate of 250 packets per second. Be sure to include correct units for each answer.
a) What is the peak data rate out of the router in one second?
b) What is the long term average data rate out of the router?
c) What is the maximum burst size?