Student Exam Questions

• Lisa Yeung:
  Switches are capable of generating less network traffic by?

  Which of the following technologies manage the conversion between IP addresses and host names? Domain Name System (DNS), Windows Internet Naming Service (WINS), and Network Information System (NIS) each support a form of name-adddress mapping on computer networks. WINS was designed for Microsoft Windows networks and NIS was designed for Unix networks. DNS supports overall name resolution and mapping on the Internet.

  Which utility program is designed to report whether a networked computer is responding at a given IP address, and how long these responses take?

  The maximum size of an IP datagram (including the header) is?

• Cal Woodruff
  Q link/network layer: given that mac addresses are controlled why do we need IP addresses?

  Q transport layer: how would you characterize a tcp transmission capable of reproducing human speech in a telephone conversation?

  Questions: Name 2 advantages of TCP for transporting sound packets vs UDP?

  Why would a TCP and UDP "phone call" likely have equivalent performance characteristics in practice?

  Delay is an issue with telephone speech transmission particularly if packets get lost. If packets get lost with a probability p what is the probability of a perceived delay of d seconds? Assume a negligible decoding delay to turn the packets back into sound.

• Halim Soetanto
  How do you impersonate someone's email with SMTP (spoof an email)?

  How do you know if an email might be a fake (spoof)?

• Michael Jia
  True or False? 1. Preamble is used to synchronize receiver, sender clock rates. 2. Link layer has responsibility of transferring data from one node to the dest node via appropreiate path.

  Short Question: 1. Name 3 attributes an ideal multiple access protocol should have.

  2. Compare ARP and link-layer switching carefully. (1) What kind of mapping is kept in ARP table? (2) What kind of mapping is kept in the link-layer Switch? (3) How does ARP obtain the mappings in the table? (4) How does the link-layer switch obtain the mappings?

• Mohamed Khalil
  Provide at least 3 advantages that switches have over hubs.
• Alex Hunt Name the transport and application layer protocols necessary for a client to retrieve a document containing a JPEG image from an specific URL (where the HTTP server is not know in advance).HTTP server is not know in advance).

  Another might be: As we saw in the second programming assingment that it is possible to implement reliable data transfer over UDP. Give reasons why someone might wish to do this:

• Salman Najarian (.doc)
• Bin Yan (.doc)