Possible questions for final examination.

PSTN/ISDN

  1. Define routing. What are its possible goals?
  2. What are the main functions of routing and their main characteristics?
  3. What are the advantages and disadvantages of centralized and distributed routing?
  4. Spell out abbreviations FHR, AAR, DAR, DNHR, LLR, RCAR, DCR.
  5. Explain the principle of number analysis in a telephone exchange.
  6. Explain the relationship between routing and (subscriber) number portability. Describe the architecture realizing number portability in Finland.
  7. What is meant by routing in circuit-switched networks? What is meant by dimensioning the network?
  8. Show the taxonomy of the routing systems in circuit switching.
  9. Compare the use of local and global information in routing.
  10. Describe the operating principle of alternative routing. Use an example.
  11. What is meant by an optimal route? Explain the interest conflict between one user and all users concerning optimality.
  12. Describe the principle of fixed hierarchical routing and the algorithm for routing.
  13. Explain the principles of originating office control and sequential office control using a routing tree.
  14. The nodes A, B, C and D form a completely looped network. Node E connects to A and C. Describe, from the user’s point of view, optimal routing from B to D using the augmented routing tree.
  15. What for do you need an influence graph? Give an example of the use of the influence graph.
  16. Provide an example on cross overflow and analyze the case using an influence graph.
  17. Explain the principle of adaptive routing
  18. Explain the principle of DAR routing. Explain also the use of trunk-line reservation parameters in DAR.
  19. Explain the principle of DAR. What variations of the algorithm there exists?
  20. Describe BT’s routing algorithm based on DAR.
  21. Explain the routing algorithm based on the general sticky principle.
  22. Describe the routing principle of the long-distance network of Canada.

    23. Internet

  23. What information in the Ipv4 protocol header does the Internet routing utilize?
  24. Explain the basic method for the Internet to recover from routing loops. How does the network recover from black holes.
  25. What are the current principles of Internet addressing?
  26. Considering routing(addressing), explain how the IP protocol is adapted to the underlying network.
  27. Explain how IP routing is adapted to a situation where there are several routers in one LAN segment.
  28. Describe the reception algorithm of distance vector protocol.
  29. Describe the functioning principles behind RIP using a little example network. (There are no faults in the network and all links weights are 1).
  30. Using an example, describe how RIP recovers from loosing a link. (The link weights are all equal).
  31. Show the birth of a transient routing loop in a RIP-network using an example.
  32. Show, using an example, that the RIP-network recovers from a transient routing loop.
  33. When does the use of RIP lead counting infinity?
  34. What countermeasures for routing loops can be built into distance vector protocol.
  35. Show, that a routing loop is possible even if the distance vector protocol uses poisoneous vectors.
  36. When does it pay off for the DV-protocol to send?
  37. Evaluate the applicability of the distance vector protocols to Internet routing.
  38. Illustrate the Bellman-Ford algorithm.
  39. Enumerate the basic characteristics of RIP.
  40. Illustrate the principle of Internet routing based on link state approach.
  41. Illustrate the algorithm for distributing the link states in link-state routing.
  42. How is the fractioned network re-united in link-state routing?
  43. What actions can be taken to ensure the integrity of the link-state databases in link-state routing?
  44. Illustrate the Dijkstra algorithm of shortest-path-first without alternative paths.
  45. Compare distanec-vector and link-state routing protocols. Or what are the advantages of link-state routing compared to distance-vector routing.
  46. The pros and cons of distributing packet traffic to alternative paths.
  47. Illustrate Dijkstra’s shortest-path-first algorithm that can also detect alternative paths.
  48. What are the subprotocols in OSPF? Explain the concept of adjacency in OSPF.
  49. Describe the OSPF flooding protocol in broadcast and point-to-point networks.
  50. Explain the concept of area in OSPF.
  51. Illustrate the principle of recovery from internal (to an area) failure in OSPF. How can virtual links be used in recovery?
  52. Explain the concepts of stub-area and and not-so-stubby-area in OSPF.
  53. Illustrate the algorithm with which the OSPF chooses the designated router and the Back-up designated router.
  54. Present the types of link state records and their usage in OSPF.
  55. Explain the actions relating to the age of the link state records in OSPF.
  56. Illustrate the use of OSPF’s network-LSA in reducing the size of the link-state database.
  57. Present the suitable network topology models of OSPF for ATM and Frame Relay networks.
  58. How did CIDR change Internet routing?
  59. Define Autonomous System. Describe the structure of Internet on the level of Autonomous Systems.
  60. Describe the main alternative router architectures.
  61. Describe the packet forwarding algorithm in an Internet router.

    62. PNNI

  62. Why is PNNI based on source routing?
  63. Illustrate the reference model of thePNNI node.
  64. What are the most important routing functions of PNNI?
  65. Define the conept of peer group in PNNI.
  66. How does the hierarchy of peer groups work in PNNI?
  67. Explain the concepts of logical node and logical link in PNNI.
  68. Explain the duties and election of peer group leader in PNNI.
  69. Explain the principle of topological aggregation using the PNNI logical node.
  70. Explain the phases of startup of the PNNI routing in an ATM-network
  71. Describe PNNI flooding protocol.
  72. The concept of uplink in PNNI.
  73. Illustrate the PNNI routing algorithm.
  74. Illustrate the functionality of cranckback in PNNI.

    75. IP-switching and Label switching

  75. Define the concepts of Label, FEC, Label Switching Router, Label switch and the Label switched path in a label-switched network.
  76. Explain the traffic and functional requirements, benefits and the motivation for the development of Label Switching and IP-switching. Explain also what is wrong with a pure IP network?
  77. Illustrate the principle of label-switched network using three consecutive nodes.
  78. Based on what criteria, packets can be classified into Forwarding Equivalence Classes in MPLS.
  79. What tables are needed in the nodes of the label-switched network? Illustrate the principle of allocating downstream labels bound to the address prefixes.
  80. Describe the label distribution and retention modes supported by MPLS in a network.
  81. What routing principles can be supported by MPLS networks?
  82. Compare traffic-driven and topology based IP/Label switching.
  83. Describe the principles of LDP.
  84. Describe MPLS "shim" protocol.
  85. Analyse the scalability of MPLS. How can it be improved and by how much?
  86. What requirements have been defined in MPLS for describing the traffic and functional properties of traffic trunks? How can the resource use be controlled in MPLS?
  87. Explain how constrained based routing works in MPLS?
  88. Analyse the limitations of the present day internet routing principles for an internet supporting Differentiated Services or guaranteed services. Evaluate the potential of MPLS in removing those limitations.

    89. Multicast

  89. Multicast applications and intended uses in the Internet. How does multicast communication differ from point-to-point communication.
  90. Define the graph-related concepts: graph, neighbor, simple graph, multigraph, path and loop.
  91. Define the graph-related concepts: connected graph, directed graph, tree, spanning tree and forest.
  92. Present the datastructures that are used to describe graphs.
  93. Give the algorithm that creates the minimal spanning tree from a given graph.
  94. Why the minimal spanning tree (MST) is not used in practical solutions of multicast in the Internet? How does the RPF multicast routing differ from the MST based solution?
  95. RPF algorithm and its characteristics.
  96. What are the two different ways that the multicast can be limited to a changing group of receivers?
  97. Present IGMPv2 and v3.
  98. Present the principles of DVMRP.
  99. How are the neighborhood relations taken care of in DVMRP?
  100. The construction and updating of source trees in DVMRP.
  101. The multicast algorithm of DVMRP in a router.
  102. Explain the use of cached information in DVMRP to minimize the multicast trees.
  103. The handling of Prune and Graft messages in DVMRP.
  104. The principle of MOSPF multicast routing.
  105. How does the MOSPF use Dijkstra’s algorithm?
  106. The effects of hierarchy to multicast routing in MOSPF.