Computer  Science 881
                             Quiz 4  -     Name ________________________

The next few questions apply to the SLIP network shown on the board.

1. Suppose I have correctly entered the ifconfig command defining
   the SLIP interfaces on jmw2 and jmw3 and that I have entered
    route add default 130.127.48.249 on jmw2.. Now if I do a

   > ping 130.127.48.24

   a. The command will succeed    b. The ICMP Echo Req will not even
                                     get to jmw
   c. The request will get there
      but the response won't get
      back.

2. We said that "proxy" arp was useful in making this network run
   correctly. The proxy arp command contained

    a. The HW address of jmw2 and   a. The HW address of jmw3 and
       the IP address of jmw3          the IP address of jmw2

    c. The HW address of jmw  and   d. The HW address of jmw2 and
       the IP address of jmw2          the IP address of jmw2

3. Another approach that can be used in place of proxy arp is
   to enter an explicit route on jmw.  To do this I would enter
   route add -host 130.127.48.250 gw (gateway address). The
   best choice for (gateway address) is:

   a. 130.127.48.1                   b. 130.127.48.250
      (jmw's default router)

   b. 130.127.48.118                 d. 130.127.48.249

4. Which of the following best characterizes the relationship between
   Autonomous Systems and IP Networks (such as 130.127) (Ignore any
   technicalities relating to the role of border routers here.)

   a. A single IP network typically    b. There is an exact one to one
      contains many AS's                  correspondence between IP networks
                                          and AS's.

   c. A single IP network is typically d. An AS typically contains one or
      contained in many AS's.             or more complete networks.


5. The transport used by RIP is:

   a. Raw IP packets with a private    b. ICMP
      protocol number

   c. UPD                              d. TCP

6. A routing update generated by a RIP router propogates (we are talking
   about the actual packets themselves -- not indirectly derived information)

   a. Across the entire internet       b. Across the entire AS

   c. Across the entire network        d. Only to directly attacted routers


7. Consider the network shown below. Suppose that the link
   connecting A and B has just failed and that RIP WITHOUT split
   horizon or poisoned reverse is being used... Fill in the
   routing table entries for node A  as they will appear AFTER
   the next three exchanges.

   A ----- B ----- C ----- D ----- E
          1-A     2-B     3-C     4-D







8. Now consider the following network. Assume that RIP is being
   used WITH split horizon and poisoned reverse.. Fill in the
   routing table entries for node A as they will appear after
   the next two exchanges

               F
              / \
             /   \
   A ----- B ----- C ----- D ----- E
          1-A     2-B     3-C     4-D

         B    F    C       D       E
        16   3-F  3-C     3-C     4-D
        4-C  16   16      4-C     4-D




9. Suppose a RIP routing table for node C looks like the following:

   Dest   Via   Cost
    A      A     1
    B      A     2
    C      -     0
    D      E     3
    E      E     1
    F      E     2
    G      G     1

   Draw as complete as possible a diagram of the network.







10. Which of the following is NOT an advantage of PPP over SLIP

    a. More robust error checking       b. Support for multiple network
                                           layer protocols

    c. Smaller headers                  d. Requires fewer IP addresses