Computer Science 881
                               Quiz 6        Name _________________

1. How is the scope in the key of an OUTPUT route established?








2. The occurence of multiple fib_nodes in an hash chain

   a. Will occur whenever a routing    b. Will occur whenever a routing
      table has multiple entries          table has multiple entries
                                          with the same prefix length

   c. May  occur whenever a routing    d. May  occur only if a routing
      table has multiple entries          table has multiple entries with
      with the same prefix length         the same destination address.

3. When a routing table lookup occurs for an output route

   a. Both tables will always be      a. Both tables will always be
      searched but a result found        searched but a result found
      in the local table has             in the main table has
      precendence.                       precendence.

   c. The main table will be searched d. The local table will be searched
      first and only if a route is       first and only if a route is
      not found will the local table     not found will the main table
      be searched.                       be searched.


4. Precisely what will happen in output routing if a source IP address is
   specified but the source address is not assigned to any netdevice on
   the system?







5. Precisely what will happen if both an oif and a source address are
   specified, but the source address is assigned to a netdevice
   other than the one identified by the oif.







6. How is the source address to be associated with a new UNICAST output route
   determined in each of the following three cases:

   a. key.src == 0 &&
      key.oif != 0






   b. key.src == 0 &&
      key.oif == 0






7. When the new route cache element is created, its the src, dst, and
   oif of the key that must be matched in future route cache lookups
   will be set to:

   a. The values originally passed      b. The values contained in the
      to ip_route_output()                 "new" key structure created in
                                            ip_route_output_slow()

   c. The values actually used as       d. a. b. and c. are always
      src, dst, and oif when sending       indentical so they are all true.
      the packet.

8. In a FIB lookup the zone associated with a "default" route will be
   searched:

   a. first, because most requests       b. last because it corresponds
      use the default route                 to a 0 length prefix.

   c. in random order based on a
      hash function.


9. The first test for usability of a fib_node is: fn_key_eq(k, f->fn_key)
   Precisely how is the value "k" constructed from the "key" structure.





10. For input routing how does the action of fib_validate_source()
    differ based upon whether or not "rpf" is enabled?











11. When a routing table lookup occurs for an input route

   a. Both tables will always be      a. Both tables will always be
      searched but a result found        searched but a result found
      in the local table has             in the main table has
      precendence.                       precendence.

   c. The main table will be searched d. The local table will be searched
      first and only if a route is       first and only if a route is
      not found will the local table     not found will the main table
      be searched.                       be searched.