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Determining IP Routes

Chapter Description

Learn how to decide which router is best for your needs. You will also see the basic functions of routers to aid you in your decision.


  1. What must a router have to correctly route a packet?

  2. What are the three types of routes you can use in a Cisco router?

  3. What is the difference between static and dynamic routes?

  4. How do you configure a static route on a Cisco router?

  5. What is a default route?

  6. How do you configure the default route on a Cisco router?

  7. What is administrative distance?

  8. What are the three classes of routing protocols?

  9. What is the AD for each of the following?

    • Directly connected interface
    • Static route
    • EIGRP
    • IGRP
    • OSPF
    • RIP
    • External EIGRP
    • Unknown
  10. Name two classful routing protocols.

  11. For different VLANs to communicate with each other, they need to be routed. To perform inter-VLAN routing, what two things must occur?

  12. How do you route between VLANs with ISL trunks?

  13. What commands enable routing between VLANs with 802.1Q trunks?

  14. How do distance vector routing protocols function?

  15. How do distance vector routing protocols keep track of any changes to the internetwork?

  16. Slow convergence of distance vector routing protocols can cause inconsistent routing tables and routing loops. What are some mechanisms that distance vector protocols implement to prevent these problems?

  17. What is maximum hop count?

  18. What is split horizon?

  19. What is convergence?

  20. What is route poisoning?

  21. What are hold-down timers?

  22. What are triggered updates?

  23. Which of the following are used for loop avoidance?

    1. Link-state advertisements
    2. Poison reverse
    3. Route discovery
    4. Split horizon
  24. How is routing information maintained with link-state routing protocols?

  25. What are the functions of areas and autonomous systems in link-state protocols?

  26. What are four advantages that link-state protocols have over distance vector protocols?

  27. List three disadvantages of link-state protocols as compared to distance vector protocols.

  28. What is balanced hybrid routing? Give an example of a balanced hybrid routing protocol.

  29. What is IP RIP?

  30. What four timers does IP RIP use to regulate its performance?

  31. What are the commands to enable RIP on a Cisco router?

  32. How do you stop RIP updates from propagating out an interface on a router?

  33. Which Cisco IOS command displays values associated with routing timers, the administrative distance, and network information associated with the entire router?

  34. What commands enable RIP on a router and advertise network

  35. How do you display the contents of a Cisco IP routing table?

  36. What IOS command displays RIP routing updates as they are sent?

  37. After enabling IP RIP debugging on your router, you see the following message: "RIP:broadcasting general request on Ethernet1". What causes this message?

  38. What is Interior Gateway Routing Protocol (IGRP)?

  39. What four timers does IGRP use to regulate its performance?

  40. How many paths can IGRP support?

  41. How do you enable IGRP on a Cisco router?

  42. Router A has two unequal paths to Router B. Interface S0 is connected to Router B's S0 interface at 1544 kbps, and interface S1 is connected to Router B's S1 interface at 256 kbps. By default, IGRP uses interface S0 to send traffic to Router B because it has the better metric, leaving S1 unused. How do you enable Router A to use interfaces S0 and S1 to route traffic to Router B?

  43. What are some of EIGRP's improvements over IGRP?

  44. By default, what does EIGRP use to calculate routes?

  45. In EIGRP, what is a successor?

  46. In EIGRP, what is the feasible successor?

  47. What IOS commands enable EIGRP on a Cisco router and advertise and as its directly connected networks?

  48. What command would you use to see EIGRP adjacencies?

  49. What IOS command would you use to view the EIGRP neighbor states?

  50. What routing metric is OSPF based on?

  51. How do OSPF-speaking routers build adjacencies and exchange routing tables?

  52. What does the Hello protocol do in an OSPF network?

  53. What are the five network types that OSPF defines?

  54. What is the IP multicast address of Hello protocols?

  55. If you have eight routers on an Ethernet network and you establish adjacencies with only the DR and BDR, how many circuits do you have?

  56. What is the OSPF router ID, and where does an OSPF router receive its router ID?

  57. An OSPF-enabled router has the following IP addresses configured on its interfaces:

    Ethernet 0
    Serial 0
    Ethernet 1

    What is the router ID of the OSPF-enabled router?

  58. What are link-state advertisements?

  59. How many LSAs are there in OSPF?

  60. What are five reasons why you would use OSPF instead of RIP?

  61. How do you enable OSPF on a Cisco router?

  62. What command enables a loopback interface on a Cisco router?

  63. What IOS command displays the OSPF neighbor information on a per-interface basis?