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WAN Questions

November 24th, 2018 Go to comments

If you are not sure about WAN, please read our WAN tutorial.

Question 1

Explanation

An example of the output of the “show interface serial …” command is shown below. We can see the line “Encapsulation HDLC”.

showinterfaces.jpg

Question 2

Explanation

PPP supports both synchronous (like analog phone lines) and asynchronous circuits (such as ISDN or digital links). With synchronous circuits we need to use clock rate.

Note: Serial links can be synchronous or asynchronous. Asynchronous connections used to be only available on low-speed (<2MB) serial interfaces, but now, there are the new HWICs (High-Speed WAN Interface Cards) which also support asynchronous mode. To learn more about them please visit http://www.cisco.com/en/US/prod/collateral/modules/ps5949/ps6182/prod_qas0900aecd80274424.html.

Question 3

Explanation

The advantages of leased lines include:
+ Simplicity: Point-to-point communication links require minimal expertise to install and maintain.
+ Quality: Point-to-point communication links usually offer high service quality, if they have adequate bandwidth. The dedicated capacity removes latency or jitter between the endpoints.
+ Availability: Constant availability is essential for some applications, such as e-commerce. Point-to-point communication links provide permanent, dedicated capacity, which is required for VoIP or Video over IP.

The disadvantages of leased lines include:
+ Cost: Point-to-point links are generally the most expensive type of WAN access. The cost of leased line solutions can become significant when they are used to connect many sites over increasing distances. In addition, each endpoint requires an interface on the router, which increases equipment costs.
+ Limited flexibility: WAN traffic is often variable, and leased lines have a fixed capacity, so that the bandwidth of the line seldom matches the need exactly (therefore answer D is not correct). Any change to the leased line generally requires a site visit by ISP personnel to adjust capacity.

(Reference: Connecting Networks Companion Guide Book published by Cisco Networking Academy – Page 54)

Question 4

Question 5

Explanation

The idea behind a WAN is to be able to connect two DTE networks together through a DCE network. The network’s DCE device (includes CSU/DSU) provides clocking to the DTE-connected interface (the router’s serial interface).

wan_dlci_understand

A modem modulates outgoing digital signals from a computer or other digital device to analog signals for a conventional copper twisted pair telephone line and demodulates the incoming analog signal and converts it to a digital signal for the digital device. A CSU/DSU is used between two digital lines -> A & D are correct but B & C are not correct.

For more explanation of answer D, in telephony the local loop (also referred to as a subscriber line) is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the carrier or telecommunications service provider’s network. Therefore a modem terminates an analog local loop is correct.

local_loop_modem.jpg

Question 6

Explanation

Below is an example of the output of this command:

show_controllers.jpg

The “show controllers serial …” command tells us about the type of the cable (in the case V.35 DTE cable) and the status of the physical layer of the interface. In above output we learn that there is an cable attached on S0/0 interface. If no cable is found we will see the line “No DTE cable” instead.

Question 7

Explanation

Nowadays all serial links are full-duplex (as serial interfaces have separate Rx & Tx pins) so maybe this question wants to ask about how to check the speed of the serial link. The “show interface” command gives us information about this. An example of this command is shown below:

show_interfaces_serial.jpg

In this output the speed of S0/0 interface is 1544 Kbits.

Question 8

Explanation

Full-mesh is a network topology in which there is a direct link between all pairs of nodes. Below is an example of full-mesh topology.

wan_full_mesh.jpg

Question 9

Question 10

Explanation

A newer fiber-optic media development for long-range communications is called dense wavelength-division multiplexing (DWDM). DWDM multiplies the amount of bandwidth that a single strand of fiber can support.

DWDM circuits are used in all modern submarine communications cable systems and other long-haul circuits.

Specifically, DWDM:

+ Enables bidirectional communications over one strand of fiber -> Answer A is correct
+ Assigns incoming optical signals to specific wavelengths of light (i.e., frequencies)
+ Each channel is capable of carrying a 10-Gbps multiplexed signal -> Answer E is not correct
+ Can multiplex more than 80 different channels of data (i.e., wavelengths) onto a single fiber -> Answer C is not correct
+ Can amplify these wavelengths to boost the signal strength
+ Supports SONET and SDH standards

Reference: http://www.ciscopress.com/articles/article.asp?p=2202411&seqNum=6

Question 11

Question 12

Explanation

In a dual-homed setup, the router in a company is still connected to the outside networks via only one ISP, but with two routers or two connections. When one of the dual-homed connection fails, traffic can still flow via other connection so it can tolerate the loss of a network link.

Dual_Homed.jpg

Note: Below is an example of Single Homed setup:

Single_Homed.jpg

Comments (30) Comments
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  1. Dynamic Networks
    June 16th, 2017

    (CCNA exam has 50 to 60 qns for 90minutes duration.)Now its 64 questions.

  2. Dynamic Networks
    June 16th, 2017

    (https://drive.google.com/open?id=1VmCdzjc-Ve-AwIfJP986Gp1bx2010PdF8zdE231N4iA
    Download all dumps………….. only we have correct dumps)

    Dumps changed…
    400 Question by Genius and extra 10 questions

  3. Fani
    June 18th, 2017

    hi @dynamic networks .. we can’t have access to ur link plz tell me the reason???

  4. idiott
    June 20th, 2017

    Asking IPV6 lab for exam ??
    Anyone tell me..

  5. Zigi
    June 26th, 2017

    Thank you all for your help!!

  6. jeni
    June 27th, 2017

    the link given above is blocked. fake links

  7. Lisa.sweetheart.ccna@gmail.com
    July 10th, 2017

    CAN SOMEONE PLEASE SEND ME THE LATEST DUMPS I’M WRITING VERY SOON. PLS SEND TO LISA.SWEETHEART.CCNA @ GMAIL.COM

    THANK YOU
    MWAH XOXOXO

  8. uspallata
    July 21st, 2017

    Hello, 9tut there is something wrong with the quiz. If press the link on the left and make the quiz, you will see that answers differ from those belonging to the same link on the right. As an example, try Wan questions.
    regards

  9. 9tut
    July 21st, 2017

    @uspallata: We checked but found no problem. Please notice that the answers in the quizzes are shuffled so they are not in the same order as shown here.

  10. stan
    July 31st, 2017

    can someone please send me the latest dumps as well. rrkm423@gmail dot come

    thanks

  11. HCL
    August 3rd, 2017

    Hello, I have a question. Why are there only explanations and no questions regarding what those explanations are talking about?

  12. Tee
    August 12th, 2017

    could really use the latest icnd2 or ccna dumps please email them to teeheath67 @ gmail dot com

  13. Muzafar
    August 15th, 2017

    Please Any one can send me lattest 2017 Dumps i will be thankfull to him …. my email is Smuzafar 45 at g ma il dot com

  14. Anonymous
    September 7th, 2017

    pls guys cn u pls help with dumps for CCNA pls guys m struggling here..my email is {email not allowed}

  15. vincent
    September 7th, 2017

    can u pls help with the Dumps for CCNA guys m struggling here

  16. vincent
    September 7th, 2017

    my email is {email not allowed} pls help with the dumps

  17. vincent
    September 7th, 2017

    my email is {email not allowed} pls help with the dumps for CCNA

  18. repo
    September 11th, 2017

    Which two options are valid WAN connectivity methods? (Choose two.)
    A. PPP
    B. WAP
    C. DSL
    D. L2TPv3
    E. Ethernet

  19. saed
    September 26th, 2017

    Hi, pls help me, I have an exam next week sen me last dumps to my email {email not allowed}

  20. ali
    September 29th, 2017

    Which statements about using leased lines for your WAN infrastructure are true?
    A. Leased lines provide inexpensive WAN access.
    B. Leased lines with sufficient bandwidth can avoid latency between endpoints.
    C. Leased lines require little installation and maintenance expertise.
    D. Leased lines provide highly flexible bandwidth scaling.
    E. Multiple leased lines can share a router interface.
    F. Leased lines support up to T1 link speeds.

    what is the correct answerrrrrrrrrrrr pleaaaaaaaaaaaase confiuse

  21. Anonymous
    October 13th, 2017

    B & C

  22. Bhagya
    October 15th, 2017

    @Buddy, there should be in same subnet. 192.168.11.0 or 192.168.10.0. Those two routers in different networks. /24 says 192.168.x is locked. You can change the last 3 digits only. So that connectivity will be up if those two routers become one of 192.168.10.x or 192.168.11.x.

  23. Bhagya
    October 15th, 2017

    ali, B can be happened because lease line are dedicated, not shared.. So if the ISP sends the sufficient bandwidth/throughput, no more latency or traffic issues.
    look C, it is easy of installation because point to point dedicated link with static IP. Once the connections is up, no needs to look at it again till the error are popping up. Expert knowledge is good for repairs again.

  24. mashith
    October 18th, 2017

    Thanks Anonymous will definitely do

  25. mashith
    October 18th, 2017

    is still valid from

  26. Saran
    November 7th, 2017

    hello there are only answers shown i need the
    question for my study pleaase help me

  27. Saran
    November 7th, 2017

    jkonessaran at gmail dot com this is my email

  28. Shraddha Suresh Shinde
    November 9th, 2017

    Hi, I am a Masters student having exposure to all levels- CCNA, CCNP, CCIE with wide range of topics (I can explain my situation as, good at all but expert at nothing). But, I want some assured material, or study notes, so that I can prepare only that and get CCNA R&S certified at first attempt for sure.

    Any help is appreciated.
    Help me at {email not allowed}

    Thanks!

  29. anon…
    January 1st, 2018

    hi everyone finally i passed CCNA 9xx/1000 marks
    i faced 2 lab
    1-ospf question
    2-acl
    questions were change

  30. anon…
    January 1st, 2018

    if anyone have queries .i will help

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