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EIGRP Questions

July 27th, 2019 in ROUTE 300-101 Go to comments
EIGRP Quick Summary:
+ EIGRP supports up to six unequal-cost paths.
+ EIGRP provides a mechanism to load balance over unequal cost paths (or called unequal cost load balancing) through the “variance” command.
+ The feasibility condition states that, the Advertised Distance (AD) of a route must be lower than the feasible distance of the current successor route.
+ The path that meets the feasibility condition requirement is called a feasible successor

Question 1


By default, EIGRP load-shares over four equal-cost paths. EIGRP also support unequal-cost load balancing via the “variance” command.

Question 2


The table below lists the default administrative distance values of popular routing protocols:

Routing Protocols Default Administrative Distance
OSPF 110
RIP 120
eBGP 20
iBGP 200
Connected interface 0
Static route 1

Question 3


+ The time must be properly configured on all routers.
+ A working EIGRP configuration is recommended.

Reference: https://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/82110-eigrp-authentication.html

Question 4


The following list of parameters must match between EIGRP neighbors in order to successfully establish neighbor relationships:

+ Autonomous System number.
+ K-Values.
+ If authentication is used both: the key number, the password, and the date/time the password is valid must match.
+ The neighbors must be on common subnet (all IGPs follow this rule).

Question 5


When EIGRP is configured in a point-to-multipoint Frame Relay network, although the Hub can receive routing updates sent from its Spoke routers but split horizon rule forbids the Hub from relaying advertisements back out the interface on which they were received. For example in the topology below, Hub can receive routing updated from two Spokes but it cannot relay them out of S0/0 interface again (as it is the interface where it received the updates). To solve this problem we need to disable split horizon on S0/0 interface of Hub.


The command should be (suppose EIGRP 1 is running):

Hub(config)#interface serial0/0
Hub(config-if)#no ip split-horizon eigrp 1

Therefore answer A is correct.

In Non-broadcast networks (such as Frame-Relay), multicast (and broadcast) are not allowed while EIGRP (and OSPF, RIPv2) uses multicast to send Hello and Update messages. Therefore these dynamic routing protocols would not work well under Frame-Relay. To overcome this issue we usually add the keyword “broadcast” at the end of the frame-relay map statement (for example, “frame-relay map ip 403 broadcast“). This makes EIGRP to send update via unicast instead of multicast.

Another way to resolve above issue is to use the “neighbor” command. This command also make EIGRP to communicate with its neighbors via unicast -> B is correct.

Note: Although we can use the “neighbor” command to set up EIGRP neighbor relationship but the routes cannot be advertised from the Hub to the Spoke because of split horizon rule.

Question 6


Although we can use the “neighbor” command to set up EIGRP neighbor relationship but the routes cannot be advertised from the Hub to the Spoke because of split horizon rule -> Answer D is not correct.

To overcome the split horizon rule we can use subinterface as each subinterface is treated like a separate physical interface so routing updates can be advertised back from Hub to Spokes.  -> Answer C is correct.

Note: The split horizon rule states that routes will not be advertised back out an interface in which they were received on

Question 7


The “ip summary-address eigrp” command is used to configure interface-level address summarization. EIGRP summary routes are given an administrative distance value of 5. The administrative distance metric is used to advertise a summary without installing it in the routing table.

Reference: http://www.cisco.com/c/en/us/td/docs/ios/iproute_eigrp/command/reference/ire_book/ire_i1.html

Question 8

Question 9


An example of how to configure EIGRP authentication on two routers that are connected to each other is shown below:

R1,R2(config)#key chain MYKEYS
R1,R2(config-keychain)#key 1
R1,R2(config-keychain-key)#key-string SecRetThing!

R1,R2(config)#interface serial 0/0
R1,R2(config-subif)#ip authentication mode eigrp 10 md5
R1,R2(config-subif)#ip authentication key-chain eigrp 10 MYKEYS

Question 10


When redistributing into RIP, EIGRP (and IGRP) we need to specify the metrics or the redistributed routes would never be learned. In this case we need to configure like this:

router eigrp 1
redistribute ospf 100 metric 10000 100 255 1 1500

Question 11

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  1. Peter
    December 26th, 2018

    How to get all the questions? Or pls send to my addr (pe ter h 261218 @ g mail dot com), I’ll be grateful. Thanks.

  2. maan
    March 24th, 2019

    can any one send me the questions please my addr is( maan . khlil at gmail )

  3. jury
    September 24th, 2019

    A network engineer is considering enabling load balancing with EIGRP. Which consideration should be analyzed?
    A. EIGRP allows a maximum of four paths across for load balancing traffic.
    B. By default, EIGRP uses a default variance of 2 for load balancing.
    C. EIGRP unequal path load balancing can result in routing loops.
    D. By default, EIGRP performs equal cost load balancing at least across four equal cost paths.

    Answer D; shouldnt it be atmost 4 equal cost paths instead of atleast four cost paths?

  4. jury
    October 3rd, 2019

    Question 8

    Which authentication methods are EIGRP uses?
    A. SHA
    B. MD5
    C. XDA
    D. CHAP
    E. Cisco
    A is correct aswell

  5. Anonymous
    November 16th, 2019

    I don’t think Q10 is well formulated. External routes distributed into OSPF are considered as E2 routes by the OSPF protocol, with a default seed metric of 20. Therefore, the EIGRP routes would be successfully redistributed into OSPF in this particular case.
    If the question were about redistribution of OSPF into EIGRP, then option B would be indeed the right answer. But in this case, the question simply doesn’t make sense.

  6. Aerox
    December 31st, 2019


    I’m new to this website. I’m preparing the CCNP ROUTE by stutying on the Official Certification Guide, but I would need to exercise with some questions.

    I notice the answers to questions that I don’t see. Where can I find them?

    Thanks to everyone answering

  7. Anonymous
    July 5th, 2020

    Can someone help me to find questions for the above explanations…

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