Computer  Science 881
                        Quiz 8  -         Name ________________________

1. The TCP protocol is a transport protocol that is

   a. Connection-less and         b. Connection-less and reliable.
      unreliable.

   c. Connection-oriented and     d. Connection-oriented and reliable.
      unreliable.

2. Functions that TCP must perform include

   a. Detect and discard          b. Reorder data that is received
      duplicated data                out of order

   c. Both of the above.          d. Neither of the above.

3. The method used by TCP to deal with datagrams that are lost
   or damaged is:

   a. Simply accept the errors    b. Send a NAK packet explicitly
                                     requesting a retransmission

   c. Have the sender time-out    d. All of the above.
      and retransmit.

4. We discussed reasons why constructing an efficient and reliable
   transport protocols above IP is more difficult than constructing an
   efficient and reliable point-to-point datalink protocol. One reason
   was that a wire has a constant latency but that IP couldn't guarantee
   Identify the other 2

    1 -


    2 -

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

5. 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.

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

    a. Detected because the       b. Detected because SYN2 is
       SEQ number is wrong.          unexpected in the SYN sent state

    c. Detected because the       d. Undetected and responded to
       ACK number is wrong.          with an ACK.

7. 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.

8. The sequence of states through which a SERVER passes when a client
   initiates a close is:

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

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

9. 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.

10. 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

11. 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.