Computer Science 881
                            Quiz 6             Name_______________________

Suppose host 192.168.2.15 is on the same LAN with me but that it
hasn't been contacted since my host was last booted.  If I now send
a UDP packet to 192.168.2.15...

1. ... a new neighbour structure will be created

   a. at the time the route is        b. At the time the packet is being
      resolved during the call to        transmitted by ip_finish_output2()
      ip_route_output_slow()

   c. Since we are on the same LAN
      no new neighbour structure
      is required.

2. and the sending of the ARP request packet will occur

   a. at the time the route is        b. At the time the packet is being
      resolved during the call to        transmitted by ip_finish_output2()
      ip_route_output_slow()

   c. Since we are on the same LAN
      no ARP request
      is required.

3. Suppose I send a burst of 5 UDP packets instead of just one. Which
   of the following is the most likely scenario

   a. All 5 will be successfully      b. Only the first one will be
      transmitted                        transmitted and the others dropped

   c. The first three will be sent    d. The last three will be sent
      and the last two will be           but the first two will be
      dropped                            dropped

4. In which of the SIMPLE STATES <<at entry>> to  __neigh_event_send()
   will an ARP request actually be sent.  ( NUD_IN_TIMER, NUD_CONNECTED,
   NUD_VALID are NOT simple states)





5. In which of the SIMPLE states <<at entry>> does __neigh_event_send()
   return 0.







6. Which of the following may call arp_solict() (Select all that apply)

   a. __neigh_event_send()              b. neigh_timer_handler()

   c. neigh_periodic_timer()            d. arp_rcv()



7. Identify the most typical cause of each of the following transition


  ___ a.  STALE->DELAY                   1. Expiration of the generic
                                            periodic timer

  ___ b.  DELAY->PROBE                   2. Expiration of the neighbour
                                            specific timer

  ___ c.  REACHABLE->STALE               3. Call to neigh_event_send

                                         4. Receipt of ARP_RESPONSE
  ___ d.  INCOMPLETE->REACHABLE
                                         5. Receipt of ARP_REQUEST

  ___ e.  NONE->STALE                    6. Transition doesn't normally
                                            occur
  ___ f.  DELAY->REACHABLE

  ___ g.  STALE->PROBE


8. Receipt of an ARP_REQUEST from a previously unknown neighbour

   a. causes no change to the            b. causes a new neighbour to
      neighbour structure                   be created in the CONNECTED state

   c. causes a new neighbour to be       d. causes a new neighbour to
      created in the INCOMPLETE             be created in the STALE state
      state


9. After a neighbour structure moves from the CONNECTED to STALE states
   to what REAL functions do neigh->output and the associated hh->output
   function point.

   a. neigh->output



   b. neigh->hh->output



10. Which (if any) of the above are different from what they were
    in the CONNECTED state.









11. If I send my 5 packets discussed in questions 1 and 2, and DO
    receive a valid ARP_REPLY but send nothing else what states will
    the neighbour structure pass through on its way from CONNECTED
    to FAILED.