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CCNA - EIGRP & OSPF

  1. Describe the classless enhanced distant vector routing protocol that is sometimes referred to as the hybrid protocol.
    EIGRP - Enhanced Interior Gateway Routing Protocol, includes subnet mask in it's route updates allowing you to use VLSM and summarization when designing networks.
  2. What is the default and max hop count on EIGRP?
    default is set to 100 and max hop count is 255
  3. What are the main features of EIGRP?
    • IP and IPv6 support
    • considered classless (same as RIPv2 and OSPF)
    • VLSM/CIDR support
    • support for summaries and discontiguous networks
    • efficient neighbor discovery
    • communication via RPT
    • best path selection via Diffusing Update Algorithm (DUAL)
  4. What Network layer protocols does EIGRP support?
    • IP
    • IPX
    • AppleTalk
    • IPv6
    • IS-IS
  5. How is EIGRP able to support different Network layer protocols?
    through the use of protocol-dependent modules or PDMs
  6. What 3 conditions must be met for neighborship establishment?
    • Hello or ACK received
    • AS number match
    • Identical metrics (K values)
  7. What features does OSPF provide?
    • consists of areas and autonomous systems
    • minimizes routing update traffic
    • allows scalability
    • VLSM/CIDR support
    • unlimited hop count
    • allows multi-vendor deployment (open standard)
  8. What are the following reasons you would create a OSPF in a hierarchical design?
    • to decrease routing overhead
    • to speed up convergence
    • to confine network instability to single areas of the network
  9. When is the only time that EIGRP advertises its entire routing table?
    When it discovers a new neighbor and forms an adjacency with it through the exchange of Hello packets.
  10. When EIGRP routers receive their neighbors' updates, what does it do?
    store them in a local topology table
  11. What is feasible distance?
    • This is the best metric along all paths to a remote network.
    • The route that you will find in the routing table because it is considered the best path.
  12. What is Reported/Advertised Distance?
    This is the metric of a remote network, as reported by a neighbor.
  13. What is the Neighbor Table and where is it stored?
    Where each router keeps state information about adjacent neighbors; what it's learned, i.e. address and interface. This is stored in RAM.
  14. What is the Topology Table?
    Populated by the protocol-dependent modules and acted upon by the Diffusing Update Algorithm. It contains all destination advertised by neighboring routers holding each destination address and a list of neighbors that have advertised information
  15. What is successor route and how does EIGRP use it?
    the best route to a remote network. used to forward traffic to a destination and is stored in the routing table.
  16. True or False: A feasible successor is a backup route and is stored in a topology table.
    True
  17. True or False: A successor route is stored in RAM and copied to the tftp server.
    False - successor route is stored in the topology table and copied and placed in the routing table.
  18. What is RTP and how does EIGRP use it?
    Reliable Transport Protocol is used to manage the communication of messages between EIGRP-speaking routers.
  19. Even though EIGRP may only use bandwidth and delay of the line by default, when you configure redistribution, what needs to be done?
    you have to configure all metric values
  20. How do you know or determine if EIGRP is running?
    • when you do sh ip route you should see the letter D.
    • D       172.16.40.0 [90/2195456] via 172.16.20.2, 00:00:02, Serial0/0/0
  21. How do you enable AS on a router?
    router eigrp [as value]

    - conf t, router eigrp 10
  22. What is route redistribution?
    Route redistribution is when you take a route from one routing protocol and inject it or distribute it into another protocol.
  23. Which command displays the entire routing table?
    show ip route
  24. Which command displays only the EIGRP entries in the routing table?
    show ip route eigrp
  25. Which command would you use to display all EIGRP neighbors?
    show ip eigrp neighbors
  26. You want to display the EIGRP topology, which command would you use?
    show ip eigrp topology
  27. Which command displays Hello packets sent/received between adjacent routers?
    debug eigrp packet
  28. You want to be made aware of changes and updates as they occur on your network, which EIGRP command would you use?
    debug ip eigrp notification
  29. What are reasons for creating OSPF in a hierarchical design?
    • to decrease routing overhead
    • to speed up convergence
    • to confine network instability to single areas of the network
  30. Routers that connect other areas to the backbone area with an AS are called
    ABRs - Area Border Routers and at least one interface of the ABR must be in area 0
  31. OSPF runs inside an autonomous system, but it can also connect multiple autonomous systems together. The router that connects thses ASes is called
    An ASBR or Autonomous System Boundary Router
  32. A network or router interface assigned to any given network is called
    a link
  33. An IP address use to identify the router
    the router id or RID
  34. Two or more router that have an interface on a common network, such as two routers connected on a point-to-point serial link
    this is known as a neighbor
  35. A relationship between two OSPF routers that permits the direct exchange of route updates is known as
    An Adjacency
  36. What do Hello packets and Link State Advertisements do?
    build and maintain the topological database
  37. Hello packets are addressed to
    224.0.0.5
  38. What is the list called where all OSPF routers for which Hello packets have been seen?
    the neighborship database
  39. This OSPF protocol provides dynamic neighbor discovery and maintains neighbor relationships
    Hello protocol
  40. This contains information from all of the Link State Advertisement packets that have been received for an area
    The Topological Database
  41. Describe Link State Advertisement (LSA)
    LSA is an OSPF data packet containing link-state and routing information that's shared among OSPF routers.
  42. True or False: An OSPF router will exchange LSA packets only with routers to which it has established adjacencies.
    True
  43. What is elected whenever OSPF routers are connected to the same multi-access network?
    A Designated Router or DR
  44. A hot standby for the Designated Router on multi-access links.
    Backup Designated Router or BDR
  45. Cisco likes to call these "broadcast" networks.
    multi-access network
  46. A grouping of contiguous networks and routers
    An OSPF area
  47. What do all routers in the same area share?
    a common Area ID
  48. What is something that really enhances the scalability of OSPF?
    a hierarchical network organization
  49. Networks such as Ethernet allow multiple devices to connect to (or access) the same network as well as provide a broadcast ability in which a single packet is delivered to all nodes on the network.
    Broadcast networks also called multi-access networks
  50. In OSPF, what must be elected for each broadcast multi-access network?
    A Designated Router and a Backup Designated Router
  51. This type of networks allow for multi-access but have no broadcast ability like Ethernet.
    NBMA or Non-broadcast multi-access networks such as Frame Relay, X.25 and ATM
  52. This refers to a type of network topology consisting of a direct connection between two routers that provide a single communication path.
    Point-to-point
  53. A type of network topology consisting of a series of connections between a single interface on a router and multiple destination routers.
    Point-to-multipoint
  54. What command is used to display OSPF information for one or all OSFP processes running on the router?
    sh ip ospf
  55. What command will give you information about the number of routers in the internetwork (AS) plus the neighboring router's ID?
    show ip ospf database
  56. What command displays all interface-related OSPF information?
    sh ip ospf interface
  57. Which OSPF command summarizes the pertinent information regarding neighbors and the adjacency state?
    sh ip ospf neighbor
  58. Which ospf debug command shows hello packets being sent and received on your router?
    debug ip ospf packet
  59. Which ospf debug command shows hello packets being sent and received on your router with detail?
    debug ip ospf hello
  60. Which ospf debug command shows DR and DBR elections on a broadcast and non-broadcast multi-access network?
    debug ip ospf adj
  61. When does the election process happen on a router?
    When a broadcast or non-broadcast multi-access network is connected to a router and the link comes up. (Think Ethernet or Frame Relay)
  62. Two routers won't become neighbors unless they agree on the following:
    • Area ID
    • Authentication
    • Hello and Dead Intervals
  63. What is crucial to the Destination Router (DR) and Backup Destination Router (BDR)?
    Neighbors and Adjacencies
  64. What are Adjacent Routers?
    Routers that go beyond the simple Hello exchange and proceed into the database exchange process.
  65. What occurs during the adjacency process?
    OSPF elects one router to be a designated router (DR) and one router to be a backup designated router (BDR) on each multi-access segment. The BDR is elected as a backup router in case the DR goes down
  66. How is Designated Router and Backup Designated Router election process accomplished?
    Via the Hello protocol. Hello packets are exchanged via IP multicast packets on each segment, but only segments that are broadcast and non-broadcast multi-access networks will perform DR and BDR elections.
  67. If all routers have the default priority set, which is will become the DR for that segment?
    the router with the highest Router ID
  68. What are Loopback interfaces?
    logical interfaces, which are virtual, software-only interfaces; they are not real router interfaces
  69. What reason would you decide to configure a loopback interface on a router?
    Because if you don't, the highest IP address on a router will become that router's RID.
  70. What is important that you must understand about shortest path first tree that is used by the router?
    that the tree consists only of networks that exist in the same area as the router itself does
  71. Cisco bases link cost on what type of metric?
    Bandwidth
  72. An interface set with a bandwidth of 64,000 would have a default cost of?




    B. 1,563
  73. OSPF uses a metric referred to as?
    Cost
  74. This metric is associated with every outgoing interface included in an SPF tree.
    Cost
  75. What is another way to configure DR and BDRs in OSPF?
    using "fix" elections instead of using loopback interfaces
  76. You can see the elections occur on a broadcast or non-broadcast multi-access network using which command?
    debug ip ospf adj
  77. What is the distance of the successor route called?
    feasible distance
Author
lokeey
ID
211157
Card Set
CCNA - EIGRP & OSPF
Description
Configure, verify, and troubleshoot basic router operation and routing on Cisco devices
Updated

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