1. Is EIGRP a distance vector or a link state routing protocol?

    Distance Vector 

  2. What is the maximum configured bandwidth EIGRP will use on a link?  Can this percentage be changed? 

    50%  IP bandwidth 

  3. How do EIGRP and IGRP differ in the way they calculate the composite metric? 

    EIGRP uses the same formula as IGRP to calculate its composite metric. However EIGRP scales the metric components by 256 to achieve a fner metric granularity 

  4. What are the four basic components of the EIGRP?

     

    Protocol Dependent Modules ( IP ) 

    Rliable Transport Protocol 

    Diffusing Update algorithm 

    Neighbor Discovery/Recovery 


  5. In the context of EIGRP, what does the term reliable delivery mean? Which two methods ensure reliable delivery of EIGRP packets? 

    EIGRP use Reliable transport protocol(RTP) to manage that/

    a. Reliable multicae 224.0.0.10 Each neighbor receiving a reliably multicast packet will unicast an acknowlegement 

    b.Ordered delivery is ensured by including two sequence numbers in the packet


     

  6. Which mechanism ensures that a router is accepting the most recent route entry?

    Sequence number ensure that a router is receiving the most recent route entry. 


  7. What is the multicase IP address used by EIGRP? 

    224.0.0.10

  8. Waht are the packet types used by EIGRP?

    Hello 

    ACKs

    Updates ( use replable delivery) 

    Querys and REplies

    Requests 


  9. At what interval, by defualt, Are EIGRP Hello packets sent?

    5 seconds Hellos are multicsat every 5 seconds, minus a small random time to prevent syc. 

  10. Waht is the default hold time? 

    15 seconds 

    3 times of hellos times. 


  11. Waht is the difference between the neighbor table and the topology table? 

    The neighbor table stores informaiton about EIGRP-speaking neighbors. 

    The topology table list all the known routes that have feasible successors. 


  12. What is a feasible distance? 


    The feasible distance to a destination is a router's lowest calculated distance to the destination. 


  13. Waht is the feasibility condition? 

    The feasiblilty condition is satisfied if a neighbor's advertised distance to a destination is lower than FD. 


  14. Waht is a feasible successor?

    A feasible successor to a destination is a neighbor that satisfies the FC for that destination. 

  15. What is  a successor? 

    A successor to a destination is a feasible successor is currectly being used as a next hop to the destinaton. 

  16. What is the difference between an active route and a passive route? 

    A route is active on a particular router if the routers has queried its neighbors for a feasible successor and has not yet received a reply from every queried neighbor. 

    The route is passive when there are no outstanding queries. 

  17. What causes a passive route to become active?

    A route becomes active when no feasible successor exists in tis topology tables. 

  18. What causes an active route to become passive? 

    An active route becomes passive when a reply has been received from every queried neighbor. 

  19. What does stuck-in-active mean? 

    If a router does not receive a reply from a queried neighbor whithin the active time( 3minutes) the route declared stuck-in-active. A responese with an infinite metric is entered on the neighbor's behalf to satisfy DUAL. The neighbor is deleted from the neighbor table. 

  20. What is the difference between subnetting and address aggregation? 

    从一个IP网络地址产生一组子网地址，称为子网化。地址聚合指的是从一组网络或子网地址汇总出一个网络地址。 

Subnetting is the practive of creating a group of subnet address from a single IP network address. 


Address aggregation is the practice of summarizing a group of netowrk or subnet address with a single IP network address.