CS 417 Exam 1

Fall 2005

    Part I - 40 Points

  1. 7 points
    You need to set up a network of 40,000 machines on the Internet. Using class-based addressing, you would need a class B network. Its 16-bit host address will allow addressing over 65,000 hosts, leading to over 25,000 unused addresses. Will CIDR help? If yes, explain how. If not, explain why not.
  2. 7 points
    In what way does the operating system have to play a role in a NUMA (Non-Uniform Memory Access) architecture?
  3. 6 points
    How does DCE RPC add an extra layer of transparency over Sun (ONC) RPC?
  4. 6 points
    What is the purpose of a port number in TCP and UDP?
  5. 6 points
    Explain the purpose of an IDL in RPC.
  6. 6 points
    (a) What is an advantage of late binding over early binding?
    (b) What is an advantage of early binding over late binding?

    Part II - 60 Points

    For each statement, select the most appropriate answer.
  7. A serializable class in Java:
    (a) guarantees that an object is reference by only one thread at a time.
    (b) ensures that valid remote references can be created for that object.
    (c) allows remote object references to be registered with the rmiregistry name server.
    (d) ensures that the object can be marshaled into a network message.
  8. A TCP header does not contain a
    (a) checksum.
    (b) sequence number.
    (c) timestamp.
    (d) source port.
  9. The portmapper under Sun (ONC) RPC:
    (a) allocates ports to server processes that host RPC functions.
    (b) allocates ports to clients that use RPC.
    (c) maps external port numbers to internal ones to allow Internet access to RPC services.
    (d) allows clients that use RPC to look up the port number of a server that hosts RPC functions.
  10. Which answer most accurately reflects the positions of TCP and UDP on the OSI protocol stack:
    (a) TCP: network (layer 3) UDP: network (layer 3).
    (b) TCP: network (layer 3) UDP: transport (layer 4).
    (c) TCP: transport (layer 4) UDP: network (layer 3).
    (d) TCP: transport (layer 4) UDP: transport (layer 4).
  11. The Address Resolution Protocol (ARP):
    (a) finds the IP address corresponding to a host name.
    (b) finds the MAC (e.g., ethernet) address corresponding to an IP address.
    (c) resolves the route to the destination host.
    (d) finds the IP address corresponding to a MAC (e.g., ethernet) address.
  12. Which of the following is not true about Microsoft ORPC?
    (a) It uses an interface definition language.
    (b) Clients send requests to increment a remote reference.
    (c) Servers periodically send a ping set of all remote references to the client.
    (d) It supports an interface pointer identifier.
  13. DCE RPC enhanced Sun (ONC) RPC by:
    (a) Introducing remote reference counting.
    (b) Adding support for objects.
    (c) Introducing a unique ID number to identify remote services.
    (d) Using XML to marshal requests.
  14. How does ARP ensure that responses to ARP queries come from the proper host?
    (a) The query is sent only to the proper machine.
    (b) The query is made over an encrypted connection.
    (c) The response contains a checksum.
    (d) There is no mechanism to ensure that the response comes from the proper host.
  15. Microsoft .NET does not use:
    (a) XIDL (eXtensible Interface Definition Language)
    (b) SOAP (Simple Object Access Protocol)
    (c) WSDL (Web Service Definition Language)
    (d) HTTP (Hypertext Transport Protocol)
  16. Which of the following addresses does not belong to the network 1.15.8.0/22?
    (a) 1.15.10.5
    (b) 1.15.11.101
    (c) 1.15.9.15
    (d) 1.15.12.2
  17. The Domain Name Service (DNS):
    (a) finds the IP address corresponding to a host name.
    (b) finds the MAC (e.g., ethernet) address corresponding to an IP address..
    (c) resolves the route to the destination host.
    (d) finds the IP address corresponding to a MAC (e.g., ethernet) address.
  18. TCP provides the following advantage over UDP:
    (a) It consumes fewer resources by not maintaining connection state.
    (b) It regulates the rate at which packets enter the network to reduce congestion.
    (c) It sends the source address and port number so the to identify the origin of the packet.
    (d) It provides a mechanism to retransmit missing or dropped packets.