Computer Science 481/681
                         Quiz B           Name _______________________

1. For each of the following system calls used in a client / server
   application answer S, C, or B based upon whether the call would
   normally be used by the Server, the Client or Both

   ____ a. socket()

   ____ b. bind()

   ____ c. connect()

   ____ d. listen()

   ____ e. accept()


2. Which of the following best describes the connection model used
   in the multi-threaded (multi-process) server we described in class.

   a. Each server process was       b. Each server process used the
      connected through a unique       same port and socket.
      port.

   c. Each server process used the  d. Each server process was connected
      same port but used a unique      through a unique port but they
      socket.                          all used the same socket.

Suppose a 3 way handshake is being used to establish a connection.
Let SYN1 represent a packet that carries SYN and no ack.
Let SYN2 represent a packet that carries both SYN and ACK that is
sent in response to a SYN1

3. A delayed duplicate SYN2  received the SYN sent state is
   detected because:

    a. The SEQ number is wrong.   b. The ACK number is wrong.

    c. Both SEQ and ACK are       d. SYN2 is an unexpected packet
       known to be wrong.            in the SYN sent state.

4. A delayed duplicate SYN1 received in the CLOSED / LISTEN state is

   a. detected because of wrong  b. Detected because of wrong ACK
      SEQ number.                   number.

   c. Undetected and responded   d. Responded to with a SYN 1.
      to with a SYN2.

5. A delayed duplicate SYN1 received in the ESTABLISHED state is:

    a. Responded to with RESET.   b. Responded to with a data packet
                                     specifying current ACK and SEQ.

    c. Responded to with SYN2     d. Always causes TCP to crash.

6. The sequence of states through which a CLIENT typically passes
    in a TCP session termination is:

    a. Close-wait, last-ack,      b. Fin-Wait-1, Closing, Time-Wait
       Closed                        Closed

    c. Fin-Wait-1, Fin-wait-2     d. Fin-Wait-1, Last-Ack, Closed
       Time-wait, Closed

7. The sequence of states through which a SERVER typically passes
    in a TCP session termination is:

    a. Close-wait, last-ack,      b. Fin-Wait-1, Closing, Time-Wait
       Closed                        Closed

    c. Fin-Wait-1, Fin-wait-2     d. Fin-Wait-1, Last-Ack, Closed
       Time-wait, Closed

8. The objective of the use of the Nagle algorithm is to:

   a. Improve the responsiveness of        b. Reduce the rate at which
      interactive sessions such as            applications could inject
      X applications.                         small segments into the
                                              network.

   c. Reduce the rate at which             d. Reduce the total amount of
      segments of ANY size could              DATA bytes transferred by
      be injected into the network.           interactive applications.

9. Suppose that a segment is received by a TCP. An ACK will be generated

   a. As soon as there is traffic          b. As soon as the 200 ms timer
      to send in the other direction.         expires.

   c. As soon as either (a.) or (b.)       d. As soon as both (a.) and (b.)
      occurs                                  occur

10. Ack timing is done in TCP by

   a. Starting a new 200 ms timer each     b. Using a single global timer
      time a segment is received.             that ticks every 200 ms.

   c. Using a time stamp carried in
      each arriving segment.

11. The "Bulk Dataflow" chapter identifies yet another condition that
    may result in a TCP kicking out an ACK. What is it?




12. For the following examples, answer (Yes) or (No) depending upone
    whether it represents the reprehensible practice of "shrinking
    the window"


   ___ (1)     <--- ack=4096,wnd=2048
                    seq=4096,size=1024 -->
               <--- ack=5120,wnd=2048

   ___ (2)     <--- ack=4096,wnd=2048
                    seq=4096,size=1024 -->
               <--- ack=5120,wnd=1024