Computer Science 481/681
                           Quiz 2            Name____________________


1. What is the subnet mask for a class B network in which 6 bits
   are used as a host address.

   a.


   b. Suppose my subnetwork mask is 255.255.240.0 and my host address
      is 130.127.48.1. Answer T or F depending upon whether each of
      the following is on the same subnetwork as me.

      ___ 1. 130.127.48.120

      ___ 2. 130.127.55.120

      ___ 3. 130.127.65.120

      ___ 4. 130.128.40.120


2. One entry type found in an IP routing table is a network address
   entry.  What are the other two?

   a.

   b.

   c. Which of the three types has the lowest priority?



3. Suppose that 0 and -1 are never used as a host or network address
   and that a netmask of 255.255.255.192 is used on a class C network.

   a. How many subnets are possible?



   b. How many hosts are on each subnetwork?




3. ICMP packets are

   a. Encapsulated in IP         b. Sent standalone without
      datagrams.                    even an ethernet header

   c. Have an ethernet header    d. Sent as a TCP packet.
      but no IP header.

4. Identify two DISTINCT types of messages of which the receipt
   should never result in generation of an ICMP error response.
   (We identified 5 in class.)

   a.



   b.



5. The other type of general ICMP message is the "query".  We
   identified 3 query types.. One was echo (ping). What were the
   other two.

   a.


   b.


6. Consider the network shown on the board. Assume the subnetmask is
   255.255.255.0

   a. Ingoring loopback or other special purpose entries, provide
      the routing table for H32. Assume address 140.130.3.2 is on
      interface eth0. For maximum credit provide the simplest
      functional table possible.

      Dest Address       Entry type    Interface
      ------------------------------------------
                     |               |
                     |               |
                     |               |
                     |               |
                     |               |
                     |               |


   b. Now do the same for H3. Assume address 140.130.1.3 is on eth0
      and 140.130.3.1 is on eth1. As before provide the simplest table
      possible and ingore loopback.

      Dest Address       Entry type    Interface
      ------------------------------------------
                     |               |
                     |               |
                     |               |
                     |               |
                     |               |
                     |               |
                     |               |
                     |               |

   c. If you have done part (b.) correctly then there should be no
      entry for subnet 130.140.2.0 in the table. Should network
      entries for 130.120.2.0, 130.120.3.0, and 130.120.4.0 be
      located in any table?

      If yes, where should they reside?





      If no, describe how a packet sent by H32 to H22 could be
      routed.