Computer Science 881
                            Quiz 4             Name_______________________

(For all questions referring to ARP states you should EXCLUDE
NUD_NOARP and NUD_PERMANENT from consideration and from your answer)

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. In the above scenario, at entry to ip_finish_output2()

   a. neighbour structure for         b. It will exist an be in the
      192.168.2.15 won't yet exist       NUD_CONNECTED state

   c. It will be in the               d. It will be in the NUD_NONE
      NUD_INCOMPLETE state               state

4. 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

5. 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)




6. In which of the SIMPLE states <<at entry>> does neigh_event_send()
   eventually return 1.



7. In which of the SIMPLE states <<at entry>> does a call to
   neigh_event_send() result in the sk_buff being added to the
   arp queue.



8. What happens when neigh_event_send() is called in the NUD_STALE
   state. (Please don't tell me what doesn't happen... only what
   does happen).









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


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

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

  ___ c.  DELAY->REACHABLE               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->PROBE


  ___ g.  REACHABLE->STALE


10. 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


11. 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