Home > GLBP Questions

GLBP Questions

November 15th, 2018 in SWITCH 300-115 Go to comments

Note: If you are not sure about GLBP, please read our GLBP tutorial.

Question 1

Explanation

The error message indicates a possible layer2 loop and STP configuration issues. Notice that the “duplicate address” here means the MAC address.

In order to resolve this issue, issue the show interface command to verify the MAC address of the interface. If the MAC address of the interface is the same as the one reported in the error message, then it indicates that this router is receiving its own hello packets sent. Verify the spanning-tree topology and check if there is any layer2 loop. If the interface MAC address is different from the one reported in the error message, then some other device with a MAC address reports this error message.

Reference: http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-series-switches/81565-glbp-cat65k.html#dr

Question 2

Explanation

The active virtual gateway (AVG) is responsible for answering the ARP Request for the virtual IP address. Load sharing is achieved by the AVG replying to the ARP requests with different virtual MAC addresses.

Question 3

Explanation

A GLBP group only has a maximum of four AVFs (means four virtual MAC addresses). If there are more than 4 gateways in a GLBP group then the rest will become Standby Virtual Forwarder (SVF) which will take the place of a AVF in case of failure.

Question 4

Question 5

Question 6

Explanation

GLBP members communicate between each other through hello messages sent every 3 seconds to the multicast address 224.0.0.102, User Datagram Protocol (UDP) port 3222 (source and destination).

Reference: http://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ft_glbp.html

Question 8

Question 9

Explanation

GLBP has three authentication schemes:

+ No authentication
+ Plain text authentication
+ MD5 authentication

Question 10

Question 11

Question 12

Question 13

Comments
  1. 14341
    June 23rd, 2015

    Anyone here who have encountered other GLBP questions?

  2. Sean nee boo
    July 15th, 2015

    Does anybody know if the 300-115 exam have any FHRP simulations?

  3. SAM
    August 28th, 2015

    where are all the questions :(

  4. certprepare
    August 29th, 2015

    Because of copyrighted issues, certprepare had to remove all questions and answers. You can download them at http://www.mediafire.com/view/9mq20kx0mgam6k7/SWITCH_July_2015.pdf

  5. SAM
    December 11th, 2015

    thanks i found them already while reading comments on another page :)

    cheers

  6. Jake
    December 2nd, 2016

    Please send dumps to eigrp100@gmail dot com

  7. ahemd erlrofaie
    January 17th, 2017

    Refer to the following configuration command.
    router(config)# ip nat inside source static tcp 172.16.10.8 8080 172.16.10.8 80
    Which statement about the command is true?

    A. Any packet that is received in the inside interface with a source IP port address of
    172.16.10.8:80 is translated to 172.16.10.8:8080.
    B. Any packet that is received in the inside interface with a source IP port address of
    172.16.10.8:8080 is translated to 172.16.10.8:80.
    C. The router accepts only a TCP connection from port 8080 and port 80 on IP address
    172.16.10.8.
    D. Any packet that is received in the inside interface with a source IP address of 172.16.10.8
    is redirected to port 8080 or port 80.

    here in tagwa dump it say the correct answer is a but i think it b , can any one advice

  8. iphelper
    July 12th, 2017

    @Ahemd erlrofaie, that’s for ROUTE….

  9. iphelper
    July 12th, 2017

    And you’re not the person you’re claiming to be as I have seen this name and comment back when I studied ROUTE.

  10. iphelper
    July 12th, 2017

    Oh crap, I’ve clicked the wrong section.

  11. CertPrep Nickname
    September 8th, 2017

    @iphelper

    hehe I saw that fail

  12. Kurt
    October 17th, 2017

    @Iphelper, could you please share the dummies. Here’s my gmai- kurtcobain19410. I would be very thankful.

  13. vick
    November 15th, 2017

    kindly help for sharing dumps at {email not allowed}

  14. vick
    November 16th, 2017

    vkrm657 @ gmail dot com

  15. I love butter
    December 9th, 2017

    Question 7 Explanation:
    1.VRRP uses the Multicast IP of 224.0.0.18, not 224.0.0.102. That Multicast is HSRPv2. A is false
    2. The MAC address of 0000.0c07.ac0c belongs to HSRP, specifically group 12 (0c hex to dec comes out to 12), so B is false.
    3. HSRP multicasts out from 224.0.0.2, (v2 from 224.0.0.102) not 18. So C is false.
    4. GLBP uses source and destionation UDP port 3222. So D is true.

  16. RA
    January 23rd, 2018

    why in Q6 D is not correct?

  17. 1WAY
    February 16th, 2018

    Question and explanation numbers seem out of sync since the new questions have been published.

  18. Archangel
    March 4th, 2018

    Q10——–By default, GLBP routers use the local multicast address 224.0.0.102 to send hello packets to their peers every 3 seconds over UDP 3222 (source and destination).

  19. Tinman
    March 8th, 2018

    Question 5
    Members of a GLBP group elect one gateway to be the active virtual gateway (AVG) for that group. Other group members provide backup for the AVG in the event that the AVG becomes unavailable.
    https://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ft_glbp.html#wp1039649

    A is correct

  20. Sergio
    March 12th, 2018

    Most of these questions (and most of the answers) don’t make sense…

  21. Confuse guy
    March 27th, 2018

    @RA

    Quoting Cisco

    “A. An HSRP-enabled router with preempt configured attempts to assume control as the active router when its Hot Standby priority is higher than the current active router. The standby preempt command is needed in situations when you want an occurring state change of a tracked interface to cause a standby router to take over from the active router. For example, an active router tracks another interface and decrements its priority when that interface goes down. The standby router priority is now higher and it sees the state change in the hello packet priority field. If preempt is not configured, it cannot take over and failover does not occur.”

    I guess the HRSP need preempt command configured to take over. If no preempt, it will not assume active role even the priority is higher

  22. lalaversa
    May 6th, 2018

    Q6.
    By default, the GLBP virtual gateway preemptive scheme is disabled (B is a wrong answer).
    A backup virtual gateway can become the AVG only if the current AVG fails, regardless of the priorities assigned to the virtual gateways (then A is one correct answer).
    C is surely wrong (100 is default priority).
    Also E is not correct because the redundancy scheme of VRRP enables you to preempt a virtual router backup that has taken over for a FAILING virtual router master with a higher priority virtual router backup that has become available; one master virtual router towards many backup virtual router that take over for a FAILING virtual router master.
    Then correct answers are A and D.

  23. lalaversa
    May 6th, 2018

    Q8. Correct answers C E
    Members of a GLBP group elect one gateway to be the active virtual gateway (AVG) for that group. Other group members provide backup for the AVG in the event that the AVG becomes unavailable. The AVG assigns a virtual MAC address to each member of the GLBP group. Each gateway assumes responsibility for forwarding packets sent to the virtual MAC address assigned to it by the AVG. These gateways are known as active virtual forwarders (AVFs) for their virtual MAC address.

    The AVG is responsible for answering Address Resolution Protocol (ARP) requests for the virtual IP address. Load sharing is achieved by the AVG replying to the ARP requests with different virtual MAC addresses.

    https://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ft_glbp.html#wp1027184

  24. lalaversa
    May 6th, 2018

    Q10. Correct answer is B (no C).
    GLBP members communicate between each other through hello messages sent every 3 seconds to the multicast address 224.0.0.102, User Datagram Protocol (UDP) port 3222 (source and destination).

    https://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ft_glbp.html#wp1027129

  25. lalaversa
    May 6th, 2018

    Q13. Correct answer are B E.
    GLBP supports up to 1024 virtual routers (GLBP groups) on each physical interface of a router, and up to 4 virtual forwarders per group.

    https://supportforums.cisco.com/t5/network-infrastructure-documents/glbp-overview-and-features/ta-p/3131567

  26. vty
    May 6th, 2018

    @lalaversa
    Q10. B – can’t be correct because protocol used is UDP not TCP

    By default, the GLBP gateway preemptive scheme is disabled. A backup virtual gateway can become the AVG only if the current AVG fails, regardless of the priorities assigned to the virtual gateways.

    seems like answer not formulated clearly… “They…” ?

    =====
    Q6 E is correct because in VRRP preemption is enabled by default.

    By default, a preemptive scheme is enabled whereby a higher priority virtual router backup that becomes available takes over for the virtual router backup that was elected to become virtual router master. You can disable this preemptive scheme using the no vrrp preempt command.

  27. kingkong423423
    May 30th, 2018

    New 100% Real CCNP Exam Questions

    dumps
    pro
    dot
    com

  28. Muhamad
    March 15th, 2019

    Pass on 13th march. My lab is HRSP and AAA dot1q. you should study them well.
    Few new questions, dump valid. Thanks certprepare!

    ====
    My email: muhamadawan1988(at)gmail(dot)com

  29. NetBrain
    May 10th, 2019

    I think that the answer A in question 6 is wrong ,

    i got something about 3 years of exprience with cisco devices and its not the first time that i see people dont understand whats the mean of preemption so i will try to explain this clearly as i can :

    preemption only needed when we want that our active router will stay active any time he is up and thats meen :

    if for example we have two routers R-1 & R-2 , R-1 is active beacause he got a higher priority so R-2 is standby , lets say that R-1 is power off now R-2 is active , but if R-1 is rise up and start to send HSRP multycast thats meen he bring back to live now without preemption R-1 dont get the active state again for himself , if we want that R-1 will take the active state again we need to configure preemption because by default its preemption in HSRP & GLBP are disabled.

    so lets bring back to question : if we got R1 & R2 like the past example that R1 is active because he got higher priority and we change priority for R2 thats gonna be higher from R1 than R2 will be active in the group , preemption is not take any rule here.

    I think that the answers are :
    D & E.

  30. Abdullah
    September 12th, 2019

    Q6
    Netbrain, totally agree. DE.

  31. Chaiwat Sarum
    September 25th, 2019

    Q13.
    Which two statements about GLBP is true? (Choose two)
    A. Can have 128 AVFs on an interface ==>Corect
    B. Maximum 4 AVFs allowed in a group ==>Correct
    C. Can work with dual active AVGs ==>not correct
    D. Can have 6 AVFs in a group ==>not correct
    E. GLBP supports up to 1024 virtual routers per group. ==>not correct

    I think answers : A,B Correct

    I read a book of David Hucaby page 380

    “Active Virtual Forwarder
    Each router participating in the GLBP group can become an AVF, if the AVG assigns it that role, along with a virtual MAC address. The virtual MAC addresses always have the form 0007.b4xx.xxyy. The 16-bit value denoted by xx.xx represents six 0 bits followed by a 10-bit GLBP group number. The 8-bit yy value is the virtual forwarder number”

  32. alba
    October 2nd, 2019

    Q6
    i think answer A is not correct.
    D & E is correct.

    https://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ft_glbp.html#wp1039649

    A backup virtual gateway can become the AVG only if the current AVG fails, regardless of the priorities assigned to the virtual gateways. You can enable the GLBP preemptive scheme using the glbp preempt command. Preemption allows a backup virtual gateway to become the AVG, if the backup virtual gateway is assigned a higher priority than the current AVG.
    because A is not correct…

  33. BlueMoon
    October 9th, 2019
  1. No trackbacks yet.