CSCI 547                               Midterm Exam                                   Fall 2006

Closed Book, Closed Notes

Name: _________________________________

Q1(6  points): In computer networking fields, standard organizations can be classified into three levels: National, Regional, and International level.

a) Name two organizations at National level in US.

b) Name two organizations at Regional level

c) Name two organizations at International level

Q2(3 points): What is SAP(Service Access Point)?

Q3(2 points): Which organization, under ISOC(Internet Society), is responsible for the Internet Standards?

Q4(6 points): Point out the differences between “persistent http” and “non-persistent http”.

Q5(4 points): Point out the difference(s) between “persistent http without pipelining” and “persistent http with pipelining”.

Q6(4 points): When we need to input some information in an http session, there are two ways to do that; Post method and URL method. Explain how the “URL method” works.

Q7(6  Points): List three cases where “cookies” can be used.

Q8(8  points):

a) In TCP/IP protocol suite, some protocols are stateful and some are stateless. Two

      examples of stateless protocols are 1) __________ 2) _________. Stateless

      protocols’ main advantage is ______________________________________

b) Two examples of stateful protocols are 1) __________ 2)____________. Stateful

      protocols’ main advantage is ______________________________________

Q9(6  Points): What are the three e-mail access protocols for the retrieval of e-mails by clients?

Q10(4  points): Describe how an e-mail system finds the IP address of an e-mail server. In other words, when we send an e-mail to john@somewhere.com, how your e-mail server finds the IP address of the mail server at “somewhere.com” without knowing the server’s name(for example, mail.somewhere.com).

Q11(4 points): What is MIME(Multipurpose Internet Mail Extensions)?

Q12(4 points): Which protocol does DNS use, TCP or UDP? Why?

Q13(8 points): TCP or UDP ports are divided into three ranges(kinds).

a) The names of the three ranges are?

b) Who controls them?

Q14(6 points): Describe how a concurrent server handles simultaneous multiple client connections.

Q15(4 points): What are the components of 4-tuple that make any TCP connection unique?

Q16(9 points): There are 3 ARQ(Automatic Repeat Request) protocols

a) Name them

b) What are the buffer requirements for sender and receiver for each ARQ protocol?

Q17(6  points): Discuss the two reasons why TCP needs 3-way handshaking for connection establishments.

Q18(10  points) TCP’s congestion control:

a) What is “congestion window”?

b) Can Congestion Window become wider than RcvWindow?

c) TCP adjusts its congestion window when a “loss condition” occurs. What are the two things that TCP uses to detect congestion condition?

d) Describe TCP’s “Slow Start”.