Computer  Science 826
                        Quiz 4  -         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. 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.

3. Which of the following is the primary difference between a reliable BYTE
   stream service and a reliable MESSAGE stream service.

   a. The byte stream service requires    b. The reliable byte stream
      byte oriented sequence numbers but     service doesn't guarantee
      the message service requires           message boundaries will
      packet oriented sequence numbers.      be preserved.

   c. The byte stream service permits     d. All of the above
      variable packet size but the
      message service requires fixed
      size.

4. The service provided by TCP is

   a. reliable byte stream                 b. reliable message stream

   c. both a. and b.                       d. neither a. nor b.

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.
   Identify two of them:


    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 SYN1 received the SYN sent state is:
   detected because:

    a. Detected because the       b. Detected because SYN1 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 SYN2

7. 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 cause a transition
       ACK number is wrong.          to the established state.

8. 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.


9. In a typical client/server TCP connection which passes through the
   "SYN SENT" state:

   a. server                      b. client

   c. both                        d. neither

10. The initial sequence number used when a TCP connection is
    setup is typically:

    a. zero                       b. the port number

    c. produced by a random       d. derived from a clock
       number generator

11. In examining a large collection of TCP packets flowing through the
    Internet which of the following flag bits would most often be
    found to have the value "1".

    a. SYN                        b. FIN

    c. RST                        d. ACK