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CCNA – WAN 2

April 14th, 2011 Go to comments

Here you will find answers to WAN Questions – Part 2

If you are not sure about Frame Relay, please read my Frame Relay tutorial.

Question 1

Users have been complaining that their Frame Relay connection to the corporate site is very slow. The network administrator suspects that the link is overloaded. Based on the partial output of the Router#show frame relay pvc command shown in the graphic, which output value indicates to the local router that traffic sent to the corporate site is experiencing congestion?

BECN.jpg

A. DLCI=100
B. last time PVC status changed 00:25:40
C. in BECN packets 192
D. in FECN packets 147
E. in DF packets 0

 

Answer: C

Explanation

First we should grasp the concept of BECN & FECN through an example:

BECN_FECN.jpg

Suppose Router A wants to send data to Router B through a Frame Relay network. If the network is congested, Switch 1 (a DCE device) will set the FECN bit value of that frame to 1, indicating that frame experienced congestion in the path from source to destination. This frame is forwarded to Switch 2 and to Router B (with the FECN bit = 1).

Switch 1 knows that the network is congesting so it also sends frames back to Router A with BECN bit set to 1 to inform that path through the network is congested.

BECN_FECN_2.jpg

In general, BECN is used on frames traveling away from the congested area to warn source devices that congestion has occurred on that path while FECN is used to alert receiving devices if the frame experiences congestion.

BECN also informs the transmitting devices to slow down the traffic a bit until the network returns to normal state.

The question asks “which output value indicates to the local router that traffic sent to the corporate site is experiencing congestion” which means it asks about the returned parameter which indicates congestion -> BECN.

Question 2

When troubleshooting a Frame Relay connection, what is the first step when performing a loopback test?

A. Set the encapsulation of the interface to HDLC.
B. Place the CSU/DSU in local-loop mode.
C. Enable local-loop mode on the DCE Frame Relay router.
D. Verify that the encapsulation is set to Frame Relay.

 

Answer: A

Explanation

The first thing when performing a loopback test on a Frame Relay connection is to reconfigure the encapsulation of the interface to HDLC protocol instead of Frame Relay protocol. The main reason is Frame Relay requires a pair of DCE/DTE which cannot be used in a loopback test.

For more information about steps of trouble shooting Frame Relay, please read: http://www.cisco.com/en/US/tech/tk713/tk237/technologies_tech_note09186a008014f8a7.shtml#topic20

For your information, below is a paragraph quoted from the above link:

“Serial0 is down, line protocol is down”

This output means you have a problem with the cable, channel service unit/data service unit (CSU/DSU), or the serial line. You need to troubleshoot the problem with a loopback test. To do a loopback test, follow the steps below:

1. Set the serial line encapsulation to HDLC and keepalive to 10 seconds. To do so, issue the commands encapsulation hdlc and keepalive 10 under the serial interface.
2. Place the CSU/DSU or modem in local loop mode. If the line protocol comes up when the CSU, DSU or modem is in local loopback mode (indicated by a “line protocol is up (looped)” message), it suggests that the problem is occurring beyond the local CSU/DSU. If the status line does not change states, there is possibly a problem in the router, connecting cable, CSU/DSU or modem. In most cases, the problem is with the CSU/DSU or modem.
3. Ping your own IP address with the CSU/DSU or modem looped. There should not be any misses. An extended ping of 0×0000 is helpful in resolving line problems since a T1 or E1 derives clock from data and requires a transition every 8 bits. B8ZS ensures that. A heavy zero data pattern helps to determine if the transitions are appropriately forced on the trunk. A heavy ones pattern is used to appropriately simulate a high zero load in case there is a pair of data inverters in the path. The alternating pattern (0×5555) represents a “typical” data pattern. If your pings fail or if you get cyclic redundancy check (CRC) errors, a bit error rate tester (BERT) with an appropriate analyzer from the telco is needed.
4. When you are finished testing, make sure you return the encapsulation to Frame Relay.

Question 3

What occurs on a Frame Relay network when the CIR is exceeded?

A. All TCP traffic is marked discard eligible.
B. All UDP traffic is marked discard eligible and a BECN is sent.
C. All TCP traffic is marked discard eligible and a BECN is sent.
D. All traffic exceeding the CIR is marked discard eligible.

 

Answer: D

Explanation

Committed information rate (CIR): The minimum guaranteed data transfer rate agreed to by the Frame Relay switch. Frames that are sent in excess of the CIR are marked as discard eligible (DE) which means they can be dropped if the congestion occurs within the Frame Relay network.

Note: In the Frame Relay frame format, there is a bit called Discard eligible (DE) bit that is used to identify frames that are first to be dropped when the CIR is exceeded.

Question 4

What are two characteristics of Frame Relay point-to-point subinterfaces? (Choose two)

A. They create split-horizon issues.
B. They require a unique subnet within a routing domain.
C. They emulate leased lines.
D. They are ideal for full-mesh topologies.
E. They require the use of NBMA options when using OSPF.

 

Answer: B C

Question 5

The output of the show frame-relay pvc command shows ”PVC STATUS=INACTIVE”. What does this mean?

A. The PVC is configured correctly and is operating normally,but no data packets have been detected for more than five minutes.
B. The PVC is configured correctly, is operating normally and is no longer actively seeking the address the remote route,
C. The PVC is configured correctly, is operating normally and is waiting for interesting to trigger a call to the remote router.
D. The PVC is configured correctly on the local switch, but there is a problem on the remote end of the PVC.
E. The PVC is not configured on the switch.

 

Answer: D

Explanation

The PVC STATUS displays the status of the PVC. The DCE device creates and sends the report to the DTE devices. There are 4 statuses:

+ ACTIVE: the PVC is operational and can transmit data
+ INACTIVE: the connection from the local router to the switch is working, but the connection to the remote router is not available
+ DELETED: the PVC is not present and no LMI information is being received from the Frame Relay switch
+ STATIC: the Local Management Interface (LMI) mechanism on the interface is disabled (by using the “no keepalive” command). This status is rarely seen so it is ignored in some books.

Question 6

Which encapsulation type is a Frame Relay encapsulation type that is supported by Cisco routers?

A. Q933-A Annex A
B. IETF
C. ANSI Annex D
D. HDLC

 

Answer: B

Explanation

Cisco supports two Frame Relay encapsulation types: the Cisco encapsulation and the IETF Frame Relay encapsulation, which is in conformance with RFC 1490 and RFC 2427. The former is often used to connect two Cisco routers while the latter is used to connect a Cisco router to a non-Cisco router. You can test with your Cisco router when typing the command Router(config-if)#encapsulation frame-relay ? on a WAN link. Below is the output of this command (notice Cisco is the default encapsulation so it is not listed here, just press Enter to use it).

Frame_Relay_encapsulation_type.jpg

Note: Three LMI options are supported by Cisco routers are ansi, Cisco, and Q933a. They represent the ANSI Annex D, Cisco, and ITU Q933-A (Annex A) LMI types, respectively.

HDLC is a WAN protocol same as Frame-Relay and PPP so it is not a Frame Relay encapsulation type.

Question 7

Router A is unable to reach Router B. Both routers are running ios version 12.0. After reviewing the command output and graphic, what is the most likely cause of the problem?

map_DLCI.jpg

A. incorrect bandwidth configuration
B. incorrect LMI configuration
C. incorrect map statement
D. incorrect IP address

 

Answer: C

Explanation

With this topology and the DLCI, we can only think of “incorrect map statement”. From the topology we can deduce traffic with a DLCI of 75 will be sent to 192.168.2.1 but the text below wrongly shows “DLCI 50″ for the next router 192.168.2.1 -> C is correct.

Comments (305) Comments
Comment pages
1 2 3 4 7 801
  1. Eng-Support
    February 11th, 2012

    Question 5

    The output of the show frame-relay pvc command shows ”PVC STATUS=INACTIVE”. What does this mean?

    A. The PVC is configured correctly and is operating normally,but no data packets have been detected for more than five minutes.
    B. The PVC is configured correctly, is operating normally and is no longer actively seeking the address the remote route,
    C. The PVC is configured correctly, is operating normally and is waiting for interesting to trigger a call to the remote router.
    D. The PVC is configured correctly on the local switch, but there is a problem on the remote end of the PVC.
    E. The PVC is not configured on the switch.

    Answer: D

    is PVC configured on local switch or router ,, is it correct answer isn’t it?

  2. KOOLS
    February 24th, 2012

    frame relay had quit different questions today for the test.

  3. Udana Shasthree
    February 28th, 2012

    A Cisco router that was providing frame relay connectivity at a remote site was replaced with a different vendor’s frame relay router.Connectivity is now down between the central and remote site.What is most likely cause of the problem?

    A)mismatched lmi type
    B)incorrect DLCI
    C)mismatched encapsulation type
    D)incorrect ip address mapping

    the answer provided this question is C
    but I think it should be A.because other vendor’s router is also a flame relay router.so encapsulation should be frame relay.other vendor’s frame relay router’s lmi type is not cisco by default.So I suggest the answer most likely to be A..

    please help guys….

  4. Amar
    March 3rd, 2012

    what are two characteristics of frame relay point-to-point subinterfaces?
    A. They create split-horizon issues.
    B. They require a unique subnet within a routing domain.
    C. They emulate leased lines.
    D. They are ideal for full-mesh topologies.
    E. They are require the use of NBMA options when using OSPF.

    Answer: B,C

    Please anyone explain it.
    Thanks

  5. Lif
    March 6th, 2012

    Appreciate if anybody send me latest CCNA dumb,going to exam on March 25 2012
    zahmif@yahoo.com

  6. link
    March 8th, 2012

    @ amar
    well the emulation part i can explain, remember subinterfaces are like virtual ports you create, therefore its like you are adding a port logically. these ports can be configured with ip addesses etc and even be used for routing or configuring the router ID(thats a thing youll see alot in ospf)

    the unique subnet thing, id say is because they need to be a different network than the physical one to avoid routing issues etc

    hope it helps and its correct, im teaching myself ccna :p

  7. Michel
    March 8th, 2012

    Hi,
    i going to exam on 10th march and i have prepared only 9tut simulation ac anyone tll me it is sufficient or not.

  8. Engoo1
    March 16th, 2012

    Appreciate if anybody send me latest CCNA dumb,going to exam within this week

    It0312@yahoo.com

  9. Bishop
    March 18th, 2012

    @Ranjitha you’re correct with show interface serial

    http://www.ciscopress.com/articles/article.asp?p=170741&seqNum=9

  10. Peloss
    March 18th, 2012

    Hello guys, according to http://www.cisco.com/en/US/docs/ios/12_1/wan/command/reference/wrdfrely.html#wp1022344 , answer 1 show frame-relay map is correct.

    Router# show frame-relay map

    Serial 1 (administratively down): ip 131.108.177.177
    dlci 177 (0xB1,0x2C10), static,
    broadcast,
    CISCO
    TCP/IP Header Compression (inherited), passive (inherited)

    CISCO – Indicates the encapsulation type for this map; either CISCO or IETF.

  11. Rfc100
    March 22nd, 2012

    This statement in the explanation for Q6 is a little misleading: “HDLC is a WAN protocol same as Frame-Relay and PPP so it is not a Frame Relay encapsulation type.” It’s not a type, but it can run ‘over’ the Layer 2 encapsulation you are using in a frame relay network (PPPoFR).

  12. zahra
    March 23rd, 2012

    Hi Folks
    I have exam on 4th April.Does anybody have a latest version of exam questions!!?
    I do not have enough resources.I will be appreciate if anybody send me sth
    z_rezvanian@yahoo.com

  13. keith
    March 28th, 2012

    please send me latest dump. taking exam soon. thanks. skulldrag34@yahoo.com

  14. Seringe
    March 31st, 2012

    Please send me latest dump on want to sit exam april.
    Thanks

  15. Seringe
    March 31st, 2012

    my e-mail is (sas66_2007@hotmail.com) please send me latest dump want to give exams soon.
    Thankz

  16. nperik
    April 3rd, 2012

    In today’s exam the show frame-relay command options were requested, for example which show frame-relay command shows the BECN and FECN counters, or which shows the type of PVC, plus the show ip eigrp, which option shows information parameters for the adjacent routers.

  17. Juliana
    April 4th, 2012

    I failed the test on March 30 due to lack of time to complete the test.
    Many questions fell Frame Relay and IP addressing.

  18. Johny
    April 5th, 2012

    @Juliana.. measure up you weaknesses and strive back to trying it again before you forget most of the staff. Don’t take too long before you do this exam again. Do practice the dump questions, your speed will increase gradually as you do them over and over. To your information you will discover some of the materials become part of you that you can easily reason them out quickly. Good luck on your second attempt.

  19. Anonymous
    April 6th, 2012

    my e-mail is (israel_bigay@yahoo.com) please send me latest dump want to give exams soon

  20. Irshad Khan
    April 10th, 2012

    i cleared my ccna 640-802 with 90% score in just 60 minutes .. there was lot of ipv6 and wireless question and 6-9 wan question and acl2 and vtp are same as 9tut little bit difference in acl permit host 2 to access fiances server and block every thing but eigrp lab are totally chanced connective between isp router to router 3 new router and also configure correct AS number. u have to be very good in EIGRP .

  21. sdishkov
    April 16th, 2012

    Hi Guys,
    Today is my great day,
    thanks God, thanks 9tut, Teskking, Cisco Netacad Academy and all training materials that I used in last year help me to reach 986 of 1000.
    I can say 9tut is the best for preparation. I can recommend this site to everyone that is interesting in CCNA certification.
    What I had today.
    Simulation:
    http://www.9tut.com/78-ccna-access-list-sim-2
    and
    http://www.9tut.com/64-ccna-eigrp-lab-question
    in my case EIGRP was wrong on R4, it was 22 and the correct one is 222 and network on the main router wasn’t advertised as well.
    I can say:
    many of all other questions are from this website as well.
    Good lock to everyone,
    Slavi

  22. mohe
    April 29th, 2012

    Alamournet@hotmail.com, need the latest Dump please

  23. Mounir Sahali
    May 7th, 2012

    Hi 9tut
    My question is why should I configure multipoint subinterface on frame relay if i can do the same on the physical interface?
    In other words what are the different between those two configuration as they fulfill our objectives

    Configuration 1

    interface Serial0/0.1 multipoint
    ip address 192.168.12.1 255.255.255.248
    frame-relay interface-dlci 102
    frame-relay interface-dlci 103
    frame-relay interface-dlci 104

    Configuration 2
    interface Serial0/0
    ip address 192.168.12.1 255.255.255.248
    frame-relay map ip 192.168.12.2 102
    frame-relay map ip 192.168.12.3 103
    frame-relay map ip 192.168.12.4 104

    and thank you in advance

  24. Ryan
    May 7th, 2012

    Can I please send me latest dumps. (ryan.j.campbell86@gmail.com) thanks

  25. janypogs
    May 8th, 2012

    Dear all,

    you may also want to check below site for some useful resources. Good luck to all of us!

    careercert.info

  26. Mariann
    May 11th, 2012

    What is the result of issuing the frame-relay map ip 192.168.1.2 202 broadcast
    command?

    A.defines the DLCI that is used for all packets that are sent to the 192.168.1.2 IP address

    B.defines the source IP address that is used in all broadcast packets on DCLI 202

    C.defines the DLCI on which packets from the 192.168.1.2 IP address are received

    D.defines the destination IP address that is used in all broadcast packets on DCLI 202

    Can anyone help?

  27. DanScott
    May 13th, 2012

    @Mariann
    I had a look in my Cisco material and you use static frame relay maps when Inverse ARP isn’t supported, so the command maps the remote network of 192.168.1.2 to the local DLCI 202…. I would say it was option C, as packets can now be received from that network and are assigned to use the DLCI 202 link.
    I think that would be my guess! C!

  28. isam
    May 14th, 2012

    hi 9tut
    iwill be entering the exam soon but i have some bending questions i desparately need answers for , so please please help me.
    first i didn’t understand csu/dsu at all.
    2. correct me if i am wrong : in order to ping a device it must be in the same subnet ? otherwise there must be a default gateway set to reach other subnets?
    3. what are the differences between ping and telnet and why i usaually see telnet done in another screen (DOS ) or some thing else than the same ios screen?
    4. what about DTE & DCE
    please contact me in my e-mail :
    ostazabgrino@hotmail.com

  29. xallax
    May 14th, 2012

    @isam
    1. csu/dsu
    http://www.youtube.com/watch?v=UWpcBs2N9gI

    2. correct.

    3. ping is… just checking if the other device is configured with an IP address and that it is reachable.
    telnet is… command line control of the other device.
    they can both be done via command line (in windows: start, run, cmd) or by using software

    4. DTE is what the internet subscriber has. the border router is considered a DTE device.
    DCE is the router the ISP has and it usually sets the clock rate (the link speed)
    http://www.youtube.com/watch?feature=player_detailpage&v=VZPkoDYP8qk#t=127s

    cheers and good luck on the exam

  30. isam
    May 14th, 2012

    9tut
    i am so happy to see the answers of my question that’s really stisfied me i very much appritiate it thank you .
    i have more questions let me start with this :
    1. i tried to make a network in packet tracer , i connected routers , swithces and PCs , i put a straight through cable between a router and a swithch but the line stay red what’s wrong ?
    2. as i know routers must be connected together through serial interfaces only is that right ?

  31. Anonymous
    May 15th, 2012

    Dear b\c the router port default shutdown u must up the port go to fast ethernet port and run command NO SHUTDOWN so the port is up.

    no router is also connected with cross cable but when you connecte the both router by cross cable no need to clock rate define on interface ok

  32. Zafar Imam
    May 15th, 2012

    Dear b\c the router port default shutdown u must up the port go to fast ethernet port and run command NO SHUTDOWN so the port is up.

    no router is also connected with cross cable but when you connecte the both router by cross cable no need to clock rate define on interface ok

  33. puneet
    May 20th, 2012

    Hi all, I am taking CCNA 640-802 exam first time on 30/05/2012. Could anyone please send me latest dumps which are valid for UK? My e-mail address is puneet_gill84@yahoo.co.uk. Many thanks.

  34. Salman from US
    May 23rd, 2012

    hey , I just nailed it today, with 933/1000, thanks to Allah. please don’t rush to answer those questions , first try to understand what they are asking because most of the questions are similar but with small trick. so be careful. Three simulations (Eigrp (AS was not configured and one of the router doesn’t connect to ISP SO YOU HAVE TO CONFIGURE static route and default route ), Acl2 Hopst B should connect to finance server it was easy, VTP WAS TRICKY but managable )

  35. Mounir Sahali
    May 23rd, 2012

    Dear Salman: Congratulation for passing the CCNA
    What I understood for your comments is that.
    For your routers to connect to the ISP router, it will need to create a default router pointing to the ISP (ip route 0.0.0.0 0.0.0.0 s0/1, where s0/1 is connected to the ISP router)
    Then you need to use the command default-information originate in order to advertise it to your routers.
    Where do you need the static route as you mention above?correct me please if I do mistake

    thank you

  36. Mounir Sahali
    May 23rd, 2012

    sorry instead of default-information originate I mean default-network

  37. MUHAMMAD RASHID
    May 28th, 2012

    I PASSED CCNA EXAM TODAY THANKS TO ALL MIGHTY ALLAH
    960/1000

  38. ddane
    June 5th, 2012

    @Mounir Sahali
    —————————————————————————————–
    “My question is why should I configure multipoint subinterface on frame relay if i can do the same on the physical interface?”
    —————————————————————————————–

    1.) For point-to-point configuration:
    In this case, each pair of the point-to-point routers is on its own subnet, and each point-to-point subinterface has a single DLCI.

    2.) For multipont configuration:
    All the participating interfaces are in the same subnet.

  39. Anonymous
    June 6th, 2012

    Becn = back
    Fecn = forward
    I should be able to remember that.

  40. God’s Grace
    June 21st, 2012

    I passed my ccna exam today Praise be to God! Thank you Jesus! and thanks to 9TUT for the tutorials and explanations, great site and thanks to xallax for your explanations to questions and thanks to http://www.examcollection.com for the dumps. Pls guys lets donate and help to keep this site up!

    48 ques for exams including 3 simulation, I had EIGRP, Acesslist2 and VTP . Make sure you practice the simulation, use packet tracer or gns3. Best wishes to all!

  41. Network messiah
    June 25th, 2012

    Hello Guys,

    Examcollection seemed not to be opening for me,I can only see 5 questions,do I need to pay or what?.

    Can anyone pls send me the latest dumps jamdixon@hotmail.com.

    cheers

  42. God’s Grace
    June 30th, 2012

    @Network messiah, search on google for a free copy of Visual CertExam Suite, vce engine, this will enable you to download full copy to see the dumps. The dumps are free! Hope this helps!

  43. mohit soni
    July 5th, 2012

    koshish jaari hai………mehnat ki ja rhi h jung jitne ki…
    jai hind…

  44. Anonymous
    July 11th, 2012

    I will be taking 640-802 exam in a few days. Although I have used this site for practicing simulation questions, I just looked at the question and answer section for the first time today.
    Going through these questions and the explanations is like taking an additional Cisco course for free. Much better than the Wendel books.

  45. jfrodo
    August 7th, 2012

    I will attempting a 2nd try on August 17th. I don’t understand why some access lists have to be placed going in or out on the router, I went over many scenarios and still can’t grasp the concepts. For example if you want to block a pc from accessing the server’s ftp port, wouldn’t you put an access list both going in and out since network traffic will go both ways? If a pc does make a connection and is accessing an ftp port wouldn’t the ftp port be active and connected from both the pc and the server’s port 20,21? In many questions preventing a pc from accessing a certain port does that mean to block the pc from downloading from that port, but not necessarily from uploading so only one thing is specified such as
    access-list 101 deny tcp 192.168.0.1 0.0.0.255 host 10.10.10.1 eq ftp
    access-list permit ip any any
    now I wrote an access list… in which direction should the access list be placed on the router connected to the pc? Please help me grasp this concept.

  46. Brandon
    August 7th, 2012

    Jfrodo When you place an ACL IN that is to block/allow packets going into the router and when you place it OUT that’s for packets going out of the router. So depending on where you place the ACL determines in our out. You have an extended ACL so it should be placed closest to the source and in this case should be placed on the LAN interface going IN to the router. I hope this helps ACLs are a pain and my suggestion just keep doing them and you’ll see it and realize WOW thats all it was.

  47. Alboma
    August 7th, 2012

    One thing to add about extended ACL is how closest to the source should be. Say there’s a router with one interface to the source, and two interfaces to LAN A and B. The ACL has a deny statement. Of course there’s a permit any statement coming after to avoid the implicit deny all. If the goal is to block traffic to A, but allow traffic to B, placing the ACL to the interface closest to the source will affect both LANs. (If the destination network address in the deny statement covers both A and B subnet) Therefore in this case the ACL should be placed to the interface to LAN A, set as outbound. Then traffic to B will not be checked.

  48. jfrodo
    August 8th, 2012

    K thanks for the info, I will continue practicing.

  49. CLS
    August 9th, 2012

    q4 why not e?

  50. CLS
    August 9th, 2012

    What are two characteristics of Frame Relay point-to-point subinterfaces? (Choose two)

    A. They create split-horizon issues.
    B. They require a unique subnet within a routing domain.
    C. They emulate leased lines.
    D. They are ideal for full-mesh topologies.
    E. They require the use of NBMA options when using OSPF.

    Why e wrong?

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