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October 23rd, 2010 in CCIE Written Go to comments

Here you will find answers to IP Services Questions

Question 1

What is the default stratum clock on a Cisco router, when you see the key word “master” configured on the NTP line?

A. 1
B. 2
C. 4
D. 6
E. 8


Answer: E

Explanation

The “ntp master” is used to configure the device as a master clock when external time synchronization is not possible; for example, the router is not connected to the Internet.

If the network has ntp master configured and it cannot reach any clock with a lower stratum number, the system claims to be synchronized at the configured stratum number, and other systems synchronize to it via NTP. By default, the master clock function is disabled. When enabled, the default stratum is 8.

In the world of NTP, stratum levels define the distance from the reference clock.  A reference clock is a stratum-0 device that is assumed to be accurate and has little or no delay associated with it (typically an atomic clock). A server that is directly connected to a stratum-0 device is called a stratum-1 server, a server that is directly connected to a stratum-1 is called a stratum-2 server and so on.

(Reference: http://www.cisco.com/en/US/products/hw/switches/ps1893/products_command_reference_chapter09186a008007dec6.html)

Question 2

Refer to the exhibit. There are two sites connected across WAN links. All intersite and intrasite links always have the same routing metric. The network administrator sees only the top routers and links being used by hosts at both LAN A and LAN B. What would be two suggestions to load-balance the traffic across both WAN links? (Choose two)

HSRP.jpg

A. Make HSRP track interfaces between the edge and core routers.
B. Replace HSRP with GLBP.
C. Add crossed intrasite links: R1-R4, R2-R3, R5-R8, and R6-R7.
D. Make R3 and R8 have lower HSRP priority than R1 and R7.
E. Replace HSRP with VRRP.

Answer: B C

Explanation

The administrator sees only the top routers (R1,R2,R5 & R7) and links being used by hosts at both LAN A and LAN B because R1 & R7 are currently active HSRP routers (notice that all the data will need to go through these routers). Next, all intersite and intrasite links have the same routing metric so these active routers will send packets to R2 or R5, not R3, R4, R6 or R8 because of the lower metric of the top routers. For example, hosts in LAN A want to send data to hosts in LAN B, they will send data to R1 -> R2 -> R5 -> R7, which has lower metric than the path R1 -> R3 -> R4 -> R6 -> R5 (or R8) -> R7.

To make the network better, we should add crossed intrasite links so that R1 & R7 can send data to both R2/R4 & R5/R6 as they have the same routing metric now -> C is correct.

Cisco Gateway Load Balancing Protocol (GLBP) differs from Cisco Hot Standby Redundancy Protocol (HSRP) and IETF RFC 3768 Virtual Router Redundancy Protocol (VRRP) in that it has the ability to load balance over multiple gateways. Like HSRP and VRRP an election occurs, but rather than a single active router winning the election, GLBP elects an Active Virtual Gateway (AVG) to assign virtual MAC addresses to each of the other GLBP routers and to assign each network host to one of the GLBP routers -> B is correct.
Note: The routers that receive this MAC address assignment are known as Active Virtual Forwarders (AVF).

Comments
  1. nrukaht
    May 17th, 2011

    HI all i have exam on 20th May any suggestion, follow this site as well one pdf file
    can any one suggest me latest Dump

  2. J90
    June 29th, 2011

    What pdf file are you reffering too?

  3. Enjoy
    December 20th, 2011

    http://www.4shared.com/folder/HSwcnsCH/_online.html

    Pass4share 205Q dums.

  4. Rodrigo Macena
    January 26th, 2012

    @Enjoy – Hei dude, this Dump is valid???

  5. Rajthemisterious
    April 29th, 2012

    Hi everybody..
    Its Roy from India….
    I currently work in Tata Communications Ltd, (India), the Leading ISP in india.
    i have a question to ask to alll of You…kindly let me know the answer if u know it…
    my question is ..
    When i give a cmd. PING 0.0.0.0 repeat 1 from a router which has many connectivities, it gives reply from a Single IP address,..no mtter how many times, i give the command….
    Also, when i give a cmd, PING 255.255.255.255 repeat 1 , i get repolies from many IP addresses……i wud apppreciate if any one is able to give a satisfactory answer to these questions…
    Also, i m preparing for CCIE Lab….kindly let me know how to improve upon my preparation scheme….

  6. test
    May 16th, 2012

    What are you directing your ping to ? 1 what ip are you pinging ( there is a network adress ? a broadcast so are you ok upstairs

  7. Zulhaidi-Bukit_Jalil
    August 28th, 2012

    I passed today 945!!!! Ultimate still valid. Now can start focus for the Lab exam…. targeting to fly Australia before Xmas.

  8. oscar
    January 25th, 2013

    if you ping 0.0.0.0 that means the default gateway will answer, and if you ping 255.255.255.255 all available addresses will answer.

  9. poop me
    March 22nd, 2013

    hi sirs, i like this site

  10. Naren
    March 31st, 2013

    Mystery of Ping Packet destined to 0.0.0.0!!

    When from am Cisco router a ping is initiated to 0.0.0.0, the router converts that to 255.255.255.255 (all broadcast address).
    There should be no difference in the output when ping packets are either destined to 0.0.0.0 or to 255.255.255.255.

    A similar behavior is observed when using ‘network 0.0.0.0 0.0.0.0 area X’ command under OSPF. The router auto-magically converts this to ‘network 0.0.0.0 255.255.255.255 area X’ which actually means that OSPF will be enabled on every interface regardless of the IP subnet configured on the interfaces.

  11. Eskinder Ketema
    April 5th, 2013

    Hi all,
    I am now preparing for the CCIE R&S written on Wendell Odom book. What other relevant sources could you advice?
    Best regards,
    Eskinder Ketema

  12. Peter K
    April 23rd, 2013

    There really isn’t any one “magical book” as I am finding out. You have to use the current Blue Print topics as a guide and try to first understand the concept behind it, and then actually try it out as small labs to actually see it in action to remember them (espcially if you don’t work on them everyday). Books that I recommend is for starters, Routin TCP/IP Vol.1 and Vol.1 which is really dense to read from cover to cover — but I did, but keep forgetting what I read months ago. So my recommendation is to read and try to understand the concept but don’t get bogged down trying to remember things.

    Another good reference for switching (certain chapters) is LAN Switching by Cisco Press. It has a better coverage in explainig CST which can be expanded to RSTP and MST as well. Other than that, I would recommend looking at various configuration guides such as BGP and OSPF Configuration Guides. With OSPF, trouble that I had initially understanding was the Stub and NSSA flooding procedures. But these, you really have to do some labs to really understand and memorize them — like what’s the point of having multiple types of stub areas and why do you need to change LSA type 7 to 5 as it moves into area 0 by ABR.

  13. Dinesh kumar
    June 18th, 2013

    thanks rstut for introducing CCIE as well with clear explanation, May be this i will CCIE certified… full credit goes to 9tut,digitaltut,certprepare,networktut &rstut…..

  14. gambo
    July 18th, 2013

    @Roy

    Did you know that in Cisco routers, you can actually point a route to the default (0.0.0.0) and the router will actually recruse it?

    example:

    ip route 192.168.215.182 255.255.255.255 0.0.0.0
    ip route 192.168.215.187 255.255.255.255 0.0.0.0

    The router will then look up it’s next-hop to 0.0.0.0 and send traffic for these 2 IPs that way!

    What I mean when you try to ping 0.0.0.0 it is actually giving you recursive ping from a network..and when you trying to ping 255.255.255.255 which is actually a broadcast that’s why you are getting reply from multiple IP..

    I hope someone else can give you more specific explanation

  15. gambo1
    July 18th, 2013

    one more point ..when you try to ping 0.0.0.0..you will get reply from localhost only…

  16. tory burch バッグ 値段
    September 3rd, 2013

    セールtory burch 仙台 tory burch バッグ 値段 http://www.bagnowadays.com

  17. Anonymous
    March 25th, 2014

    Does anyone has problem with Visual CertExam manager? I keep having the “your license has been locked” message. I tried to crack it, it was working as first and then not working anymore. Please help.

  18. Anon_tech
    March 26th, 2014

    Anonymous: Add the following lines to your hosts file and then try again.

    127.0.0.1 update.visualcertexam.com
    127.0.0.1 avanset.com
    127.0.0.1 www.avanset.com
    127.0.0.1 update.avanset.com

  19. Anon_tech
    March 26th, 2014

    *remove the http:// from the line http://www.avanset.com (got auto formatted)

  20. دانلود فیلم
    November 27th, 2014

    Very interesting,thank you
    دانلود فیلم http://hellphonefilm.com/

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