Week 3: Applications

Goals:

• Continue learning about application protocols.
• Learn about the sockets API.
  

Monday, February 6: Email

Read:

• Kurose & Ross 2.4, p. 120 - 132
• Goodman, Cormack, and Heckerman, Spam and the ongoing battle for the inbox, CACM 50(2), Feb. 2007. (Access on campus or through library.)
• Not required but also interesting: Grimes, Compliance with the CAN-SPAM act of 2003, CACM 50(2), Feb. 2007.
  

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 02-06" as the subject line of your email.

1. Kurose & Ross, 2.R16
2. What is the difference between MAIL FROM: in SMTP and From: in the mail message itself? (K&R 2.P13)
3. How does SMTP mark the end of a message body? How about HTTP? Can HTTP use the same method as SMTP to mark the end of a mesage body? Explain. (K&R 2.P14)
4. What was the most important or surprising thing you learned about anti-spam resesarch?
   
5. What's a question you still have about the reading?

Due:

• Lab 3: Measuring Throughput

• Lab 4: Application Protocols
  

Wednesday, February 8: DNS

Read:

• Kurose & Ross 2.5, pp. 132 - 146
• Vixie, DNS Complexity. ACM Queue, April 2007.
  
• Vixie, What DNS is not. ACM Queue, November 2009.
  
• Gallagher, ICANN pushes ahead with January 12 launch for new top-level domains, Ars Technica, January 5, 2012.

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 02-08" as the subject line of your email.

1. Explain the difference between recursive and iterative DNS queries. Why have both?
2. Why do DNS query and reply messages have the same format? (This is unusual for an application-layer protocol.)
3. Identify an intriguing or controversial sentence from one of Vixie's articles. Quote the sentence (with an informal citation so I know which article it is from) and explain why you chose it.
4. ICANN has just launched a process for requesting new TLDs. What social or technical implications do you see?
   
5. What questions would you like to talk about in class?
   

Friday, February 10: P2P applications; sockets

Read:

• Kurose & Ross 2.6, pp. 146 - 159
• Kurose & Ross, Interview with Bram Cohen, pp. 193 - 195
  
• Peterson & Davie 1.4, pp. 30-39 (to be distributed in class on Wednesday)
• Kurose & Ross 2.7 - 2.8 (optional, if you are familiar with Java or want to be)
  

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 02-10" as the subject line of your email.

1. Explain to a non-CS friend how BitTorrent can be faster than downloading a large file from a server.
2. Can there be freeriders in BitTorrent?  Why or why not?
3. In the "peer churn" scenario at the bottom of page 157, how could peer 3 reliably update its overlay routing information?
4. What was the most unclear point about UNIX sockets in C, in the reading from Peterson & Davie?
5. What else would you like to talk about?
   

Suggested problems: 2.P23, 2.P24, 2.P29,2.P30, 2.P33

Janet Davis (davisjan@cs.grinnell.edu)