Week 10: Multimedia

Goals:

• Compare and contrast three approaches to supporting multimedia: "making the best of best-effort", differential QoS, and guaranteed QoS.
• Understand jitter as a problem for networked multimedia applications, and techniques for addressing jitter.
• Become familiar with multimedia protocols: RTSP, RTP, RTCP, SIP.
  

Monday, April 9: Streaming media

Read:

• Kurose & Ross 7.0 - 7.3, pp. 597 -  631 (okay to skip over 7.1.4)
  

Answer the following questions. Send your answers in the body of an email to me (davisjan@cs.grinnell.edu) by 9 a.m. Please use "CSC-364 04-09" as the subject line of your email.

The first few questions are short review or computation problems. Question 5 requires more reflection.

1. Figures 7.1 and 7.2 present two schemes for streaming stored media. What are the advantages and disadvantages of each?
   
2. Explain how the Internet best-effort delivery model can result in jitter when the network is congested.
3. How does the client buffer in Figure 7.3 help to overcome jitter? Is it always effective?
   
4. Why is RTSP designed as an out-of-band protocol? What does this accomplish?
5. How do CDNs and bandwidth provisioning help to support streaming media?
   
6. What questions or problems would you like to discuss in class?
   

Due:

• Observing an Ethernet

Assigned:

• Implementing BLAST

Wednesday, April 11: Real-time protocols

Read:

• Kurose & Ross 7.4, pp. 631 - 646
  
• Peterson & Davie (3/e), 5.3.1 "Bulk Transfer (BLAST)", pp. 408 - 413 (handed out in class)
  

Answer the following questions. Send your answers in the body of an email to me (davisjan@cs.grinnell.edu) by 9 a.m. Please use "CSC-364 04-11" as the subject line of your email.

1. Why do you think RTP is impelemented is an application-layer library rather than as a transport protocol in the OS?
2. R10
3. R12
   
4. How does BLAST compare to TCP? To the protocol you designed on the first day of class?
5. Would there be any advantage to implementing RTP over BLAST instead of UDP? If so, what?
6. What questions or problems would you like to discuss in class?

Friday, April 13: Service classes & guarantees

Read:

• Kurose & Ross 7.5-7.7, pp. 646-673
  
• Interview with Henning Schulzrinne, pp. 684-686
  

Answer the following questions. Send your answers in the body of an email to me (davisjan@cs.grinnell.edu) by 9 a.m. Please use "CSC-364 04-13" as the subject line of your email.

1. R13
2. R14
3. R15
4. How is IntServ different from DiffServ? Which do you think is more challenging to implement on the Internet, and why?
5. Explain the principle of soft state in your own words. Why is it a useful idea?
   
6. What questions or problems would you like to discuss in class?

Janet Davis (davisjan@cs.grinnell.edu)