Computer  Science 826
                        Quiz 3  -         Name ________________________

1. Suppose the method proposed in class for using ping to estimate
   bandwidth  and delay is being used and the following measures are
   captured:

   Small packet (125 bytes)         4 msec            14 msec


   Big packet  (1250 bytes)        24 msec            40 msec


   a. Find the H1-H2  bandwidth in Kbits / sec (Here K is 1000 not 1024)











   b. Find the latency in milliseconds









2. Precisely why is it the case the "original traceroute" must use
   sockets of type SOCK_RAW rather than SOCK_DGRAM to send packets.





3. The "original" traceroute program whose code we reviewed in class

    a. Sends ICMP and receives ICMP      b. Sends UDP and receives UDP

    c. Sends ICMP and receives UDP       d. Sends UDP and receives ICMP

4. Assuming "original" traceroute is working correctly, how many messages
   should be received by the host initiating the traceroute for
   each packet that it transmits.

   a. 1                               b. One for each router the
                                         transmission passes through.

   c. None (unless the transmission
      succeeds in arriving at the
      destination named in the IP
      header.).


5. In the new and improved traceroute of RFC 1393, how many messages
   should be received by the host initiating the traceroute for each packet
   that it transmits.

   a. 1                               b. One for each router the
                                         transmission passes through.
   c. None (unless the transmission
      succeeds in arriving at the
      destination named in the IP
      header.).

6. An RFC 1393 traceroute is performed by sending:

    a. An ICMP request packet          b. Any IP packet that contains
       with a new code specified          the new traceroute header
       in RFC 1393                        option.

    c. Both approaches can be used.

7. In RFC 1393 traceroute the link bandwidth and MTU for each
   link is returned via:

   a. IP header options                b. a UDP packet

   c. an ICMP packet                   d. Whatever type of packet
                                          was used in the request.

8. Suppose a loose source routed message specifies three intermediate
   routers:

     S -------> R1 -------->   R2 ------->  R3  -------->  D

    a. what will be the contents (in correct order) of the source
    route options during the transmission from R2 to R3.




    b. what will be the DESTINATION address carried by the packet
       during this hop.




9. What is the maximum number of intermediate hops that can be
   specified with source routing.

   a. 4                                 b. 9

   c. Unlimited                         d. None of the above


10. When multiple "original" traceroutes are run simultaneously
    each traceroute process receives responses associated
    with the others' probes. PRECISELY how is it possible for the
    a receiver to identify those messages associated with its own
    probes.