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IPv6 OSPF Virtual Link Sim

May 8th, 2014 in Lab Sim, LabSim Go to comments

Question

TUT is a small company that has an existing enterprise network that is running IPv6 OSPFv3. However, R4’s loopback address (FEC0:4:4) cannot be seen in R1. Identify and fix this fault, do not change the current area assignments. Your task is complete when R4’s loopback address (FEC0:4:4) can be seen in the routing table of R1.

OSPFv3_IPv6_VirtualLink

Special Note: To gain the maximum number of points you must remove all incorrect or unneeded configuration statements related to this issue.

Answer and Explanation:

To troubleshoot the problem, first issue the show running-config on all of 4 routers. Pay more attention to the outputs of routers R2 and R3

The output of the “show running-config” command of R2:

OSPFIPv6v3VirtualLink_show_run_R2

The output of the “show running-config” command of R3:

OSPFIPv6v3VirtualLink_show_run_R3

We knew that all areas in an Open Shortest Path First (OSPF) autonomous system must be physically connected to the backbone area (Area 0). In some cases, where this is not possible,we can use a virtual link to connect to the backbone through a non-backbone area. The area through which you configure the virtual link is known as a transit area. In this case, the area 11 will become the transit area. Therefore, routers R2 and R3 must be configured with the area area-id virtual-link neighbor-router-id command.

+ Configure virtual link on R2 (from the first output above, we learned that the OSPF process ID of R2 is 1):

R2>enable
R2#configure terminal
R2(config)#ipv6 router ospf 1
R2(config-rtr)#area 11 virtual-link 3.3.3.3

(Notice that we have to use neighbor router-id 3.3.3.3, not R2’s router-id 2.2.2.2)

+ Configure virtual link on R3 (from the second output above, we learned that the OSPF process ID of R3 is 1 and we have to disable the wrong configuration of “area 54 virtual-link 4.4.4.4”):

R3>enable
R3#configure terminal
R3(config)#ipv6 router ospf 1
R3(config-rtr)#no area 54 virtual-link 4.4.4.4
R3(config-rtr)#area 11 virtual-link 2.2.2.2

We should check the configuration on R4:

R4>enable
R4#show running-config

You will see a wrongly configured virtual-link command. To get full mark we have to disable this command:

R4#configure terminal
R4(config)#ipv6 router ospf 1
R4(config-rtr)#no area 54 virtual-link 3.3.3.3

After finishing the configuration don’t forget to ping between R1 and R4 to make sure they work well!

Now all the configuration was done. It is weird that we can’t ping the IPv6 loopback interface of R4 (with the ping or ping ipv6 command) but we can check by using the command show ipv6 route on R1

The copying running-config startup-config command will not work but don’t worry, just skip it.

Notice: If you issue the command “show running-config” on R1, you will see these two lines:

passive-interface default
no passive-interface fa0/0 (fa0/0 is the interface connecting with R2)

These two lines make all the interfaces of R1 become passive interfaces except interface fa0/0. They are correctly configured so don’t try to disable them.

 

Other lab-sims on this site:

EIGRP Stub Sim

OSPF Sim

EIGRP OSPF Redistribution Sim

EIGRP Simlet
Policy Based Routing Sim

Comments
Comment pages
1 2 32
  1. jokie
    July 13th, 2017
  2. AnyMaster
    July 13th, 2017

    Probably the exam will ask you to ping, so do from R1 #ping ipv6 FEC0:4:4 . It will count some points!

  3. Doug Funny
    July 20th, 2017

    Is it normal to not be able to ping the OSPF published interfaces?

  4. frankie
    July 23rd, 2017

    **********************************************
    R1#sh run
    Building configuration…

    Current configuration : 1226 bytes
    !
    version 12.4
    service timestamps debug datetime msec
    service timestamps log datetime msec
    no service password-encryption
    !
    hostname R1
    !
    boot-start-marker
    boot-end-marker
    !
    !
    no aaa new-model
    !
    resource policy
    !
    memory-size iomem 5
    no ip icmp rate-limit unreachable
    ip cef
    ip tcp synwait-time 5
    !
    !
    no ip domain lookup
    !
    ipv6 unicast-routing
    !
    !
    !
    interface Loopback0
    no ip address
    ipv6 address FEC0:1::1/28
    ipv6 ospf 1 area 0
    !
    interface FastEthernet0/0
    no ip address
    duplex auto
    speed auto
    ipv6 address autoconfig
    ipv6 ospf 1 area 0
    !
    interface Serial0/0
    no ip address
    shutdown
    clock rate 2000000
    !
    interface FastEthernet0/1
    no ip address
    shutdown
    duplex auto
    speed auto
    !
    interface Serial0/1
    no ip address
    shutdown
    clock rate 2000000
    !
    interface FastEthernet1/0
    no ip address
    shutdown
    duplex auto
    speed auto
    !
    !
    !
    ip http server
    no ip http secure-server
    !
    no cdp log mismatch duplex
    ipv6 router ospf 1
    router-id 1.1.1.1
    log-adjacency-changes
    !
    !
    control-plane
    !
    !
    line con 0
    exec-timeout 0 0
    privilege level 15
    logging synchronous
    line aux 0
    exec-timeout 0 0
    privilege level 15
    logging synchronous
    line vty 0 4
    login
    !
    !
    end
    **********************************************

    R2#sh run
    Building configuration…

    Current configuration : 1015 bytes
    !
    version 12.4
    service timestamps debug datetime msec
    service timestamps log datetime msec
    no service password-encryption
    !
    hostname R2
    !
    boot-start-marker
    boot-end-marker
    !
    !
    no aaa new-model
    !
    resource policy
    !
    memory-size iomem 5
    ip cef
    !
    !
    ipv6 unicast-routing
    !
    interface Loopback0
    no ip address
    ipv6 address FEC0:2::2/28
    ipv6 ospf 1 area 0
    !
    interface FastEthernet0/0
    no ip address
    duplex auto
    speed auto
    ipv6 address autoconfig
    ipv6 ospf 1 area 0
    !
    interface Serial0/0
    no ip address
    ipv6 address autoconfig
    ipv6 ospf 1 area 11
    clock rate 2000000
    !
    interface FastEthernet0/1
    no ip address
    shutdown
    duplex auto
    speed auto
    !
    interface Serial0/1
    no ip address
    shutdown
    clock rate 2000000
    !
    ip http server
    no ip http secure-server
    !
    ipv6 router ospf 1
    router-id 2.2.2.2
    log-adjacency-changes
    area 11 virtual-link 3.3.3.3
    !
    ipv6 ospf name-lookup
    !
    control-plane
    !
    line con 0
    line aux 0
    line vty 0 4
    login
    !
    !
    end
    **********************************************

    R3# sh run
    Building configuration…

    Current configuration : 995 bytes
    !
    version 12.4
    service timestamps debug datetime msec
    service timestamps log datetime msec
    no service password-encryption
    !
    hostname R3
    !
    boot-start-marker
    boot-end-marker
    !
    !
    no aaa new-model
    !
    resource policy
    !
    memory-size iomem 5
    ip cef
    !
    !
    ipv6 unicast-routing
    !
    !
    interface Loopback0
    no ip address
    ipv6 address FEC0:3::3/28
    ipv6 ospf 1 area 11
    !
    interface FastEthernet0/0
    no ip address
    duplex auto
    speed auto
    ipv6 address autoconfig
    ipv6 ospf 1 area 54
    !
    interface Serial0/0
    no ip address
    ipv6 address autoconfig
    ipv6 ospf 1 area 11
    clock rate 2000000
    !
    interface FastEthernet0/1
    no ip address
    shutdown
    duplex auto
    speed auto
    !
    interface Serial0/1
    no ip address
    shutdown
    clock rate 2000000
    !
    !
    ip http server
    no ip http secure-server
    !
    ipv6 router ospf 1
    router-id 3.3.3.3
    log-adjacency-changes
    area 11 virtual-link 2.2.2.2
    !
    !
    control-plane
    !
    !
    line con 0
    line aux 0
    line vty 0 4
    login
    !
    !
    end
    **********************************************
    R4# sh run
    Building configuration…

    Current configuration : 795 bytes
    !
    version 12.4
    service timestamps debug datetime msec
    service timestamps log datetime msec
    no service password-encryption
    !
    hostname R4
    !
    boot-start-marker
    boot-end-marker
    !
    !
    no aaa new-model
    !
    resource policy
    !
    memory-size iomem 5
    ip cef
    !
    ipv6 unicast-routing
    !
    !
    interface Loopback0
    no ip address
    ipv6 address FEC0:4::4/28
    ipv6 ospf 1 area 54
    !
    interface FastEthernet0/0
    no ip address
    duplex auto
    speed auto
    ipv6 address autoconfig
    ipv6 ospf 1 area 54
    !
    interface FastEthernet0/1
    no ip address
    shutdown
    duplex auto
    speed auto
    !
    ip http server
    no ip http secure-server
    !
    ipv6 router ospf 1
    router-id 4.4.4.4
    log-adjacency-changes
    !
    !
    control-plane
    !
    !
    line con 0
    line aux 0
    line vty 0 4
    login
    !
    !
    end

    R4#

  5. frankie
    July 23rd, 2017

    R1#sh ipv6 route
    IPv6 Routing Table – 7 entries
    Codes: C – Connected, L – Local, S – Static, R – RIP, B – BGP
    U – Per-user Static route
    I1 – ISIS L1, I2 – ISIS L2, IA – ISIS interarea, IS – ISIS summary
    O – OSPF intra, OI – OSPF inter, OE1 – OSPF ext 1, OE2 – OSPF ext 2
    ON1 – OSPF NSSA ext 1, ON2 – OSPF NSSA ext 2
    L FE80::/10 [0/0]
    via ::, Null0
    C FEC0::/28 [0/0]
    via ::, Loopback0
    L FEC0:1::1/128 [0/0]
    via ::, Loopback0
    O FEC0:2::2/128 [110/10]
    via FE80::C202:13FF:FEB4:0, FastEthernet0/0
    OI FEC0:3::3/128 [110/74]
    via FE80::C202:13FF:FEB4:0, FastEthernet0/0
    OI FEC0:4::4/128 [110/84]
    via FE80::C202:13FF:FEB4:0, FastEthernet0/0
    L FF00::/8 [0/0]
    via ::, Null0
    R1#

  6. frankie
    July 23rd, 2017

    R1#ping ipv6 FEC0:4::4

    Type escape sequence to abort.
    Sending 5, 100-byte ICMP Echos to FEC0:4::4, timeout is 2 seconds:
    !!!!!
    Success rate is 100 percent (5/5), round-trip min/avg/max = 44/73/124 ms
    R1#

  7. frankie
    July 23rd, 2017

    check you configuration, the loopback interfaces should be in the correct ospf areas

  8. Anonymous
    August 9th, 2017

    @ frankie: Thks for the update

  9. simplyme
    August 19th, 2017

    @frankie thanks for the info mate. got it.

    R1#ping ipv6 FEC0:4::4

    Type escape sequence to abort.
    Sending 5, 100-byte ICMP Echos to FEC0:4::4, timeout is 2 seconds:
    !!!!!
    Success rate is 100 percent (5/5), round-trip min/avg/max = 72/93/108 ms
    R1#

  10. JANE
    August 19th, 2017

    in the lab I downloaded from here. R4 and R1 loopbacks are not added to the ospf process. Kindly correct

  11. Anonymous
    August 21st, 2017

    I tried without configuring lo0 at R1 and i could still see the R4 lo0 route at R1.

    ipv6 ospf 1 area 0

    @frankie, do we need to configure this at R1?

  12. Anonymous
    August 25th, 2017

    Failed today 760pts only..although I cleared all simulations,I couldn’t answer 40% of multiple choice …study hard..all dumps outdated

  13. @studdingalot
    September 4th, 2017

    @anonymous,
    What’s the sim that you have tried in your exam? Similar to these? thx

  14. Cool-Guy
    September 8th, 2017

    Hello
    My query is regarding OSPF ipv6 Simlet.
    According to Below:
    We knew that all areas in an Open Shortest Path First (OSPF) autonomous system must be physically connected to the backbone area (Area 0). In some cases, where this is not possible,we can use a virtual link to connect to the backbone through a non-backbone area. The area through which you configure the virtual link is known as a transit area. In this case, the area 11 will become the transit area. Therefore, routers R2 and R3 must be configured with the area area-id virtual-link neighbor-router-id command.
    All areas must connect to Area 0 so why we are not connecting R4 router to transit area- Area11
    it seems area 54 is not connecting to area 11 so how is area 54 not connecting but still passing routes to area 11 and area 0???
    Please can someone clarify stuck on this past 2 hours…. :)

  15. @studdingalot
    September 13th, 2017

    All sims are similar to what you see on this website , but most of the multiple choice are different …loads of DMVPN , TCP/UDP , IPV6 and simlets

  16. mantuika
    September 29th, 2017

    Cool guy, the area between AREA-0 & AREA-54 is AREA-11. That is the transit area, not 54.

  17. Moreseas
    October 3rd, 2017

    Re: Cool-Guy
    Think of it this way; Area 11 is just fine because it has at least one router in the backbone area 0, the virtual-link command is technically merging area 54 with area 11 so as to satisfy the condition of having at least one interface in the backbone area. That is a good way to look at it.
    Let me know if this helps you

  18. Chikku
    October 29th, 2017

    Anyone who took the exam recently can confirm which are the SIMs in the exam?????
    I’m gonna take it early next week.
    Please respond asap.

  19. Dgo
    October 29th, 2017

    Thank you FRANKIE

  20. Dgo
    October 29th, 2017

    Just added all of the Labs into one big GNS3.. hit me up if you are interested>

    https://plus.google.com/u/0/117541681808420450293/posts/A9s8EFryh7c

  21. nowlad
    October 30th, 2017

    @ all, please help:

    When I do on R3: no area 54 virtual-link 4.4.4.4 and on R4 no area 54 virtual-link 3.3.3.3

    Than I cannot ping FEC0:4::4 and I cannot see it with show ipv6 route ..

    Why? Is the GNS3 Lab wrong?? Please help

  22. hacker
    November 2nd, 2017

    about the show ip route on IPv6 OSPF virtual link. why FEC0:4::4 does not appear on R1. I follow all of the steps that written here on this site. PLEASE HELP..

    R1>show ipv6 route
    IPv6 Routing Table – 6 entries
    Codes: C – Connected, L – Local, S – Static, R – RIP, B – BGP
    U – Per-user Static route
    I1 – ISIS L1, I2 – ISIS L2, IA – ISIS interarea, IS – ISIS summary
    O – OSPF intra, OI – OSPF inter, OE1 – OSPF ext 1, OE2 – OSPF ext 2
    ON1 – OSPF NSSA ext 1, ON2 – OSPF NSSA ext 2
    L FE80::/10 [0/0]
    via ::, Null0
    C FEC0::/28 [0/0]
    via ::, Loopback0
    L FEC0:1::1/128 [0/0]
    via ::, Loopback0
    OI FEC0:2::2/128 [110/10]
    via FE80::C202:14FF:FEE4:0, FastEthernet0/0
    OI FEC0:3::3/128 [110/74]
    via FE80::C202:14FF:FEE4:0, FastEthernet0/0
    L FF00::/8 [0/0]
    via ::, Null0

    R4#show ipv6 route
    IPv6 Routing Table – 7 entries
    Codes: C – Connected, L – Local, S – Static, R – RIP, B – BGP
    U – Per-user Static route
    I1 – ISIS L1, I2 – ISIS L2, IA – ISIS interarea, IS – ISIS summary
    O – OSPF intra, OI – OSPF inter, OE1 – OSPF ext 1, OE2 – OSPF ext 2
    ON1 – OSPF NSSA ext 1, ON2 – OSPF NSSA ext 2
    L FE80::/10 [0/0]
    via ::, Null0
    C FEC0::/28 [0/0]
    via ::, Loopback0
    OI FEC0:1::1/128 [110/84]
    via FE80::C203:14FF:FEE4:0, FastEthernet0/0
    OI FEC0:2::2/128 [110/74]
    via FE80::C203:14FF:FEE4:0, FastEthernet0/0
    OI FEC0:3::3/128 [110/10]
    via FE80::C203:14FF:FEE4:0, FastEthernet0/0
    L FEC0:4::4/128 [0/0]
    via ::, Loopback0
    L FF00::/8 [0/0]
    via ::, Null0

  23. Dim
    November 16th, 2017

    @hacker: Look the message from @frankie. Check Loopback0 on R1 and on R4 – they aren’t participate in an OSPF process.
    So add ip ospf 1 area 0 for L0 on R1 and ip ospf 1 area 54 for L0 on R4.

  24. Dim
    November 16th, 2017

    @hacker: Sorry, a little mistake in commands:
    ipv6 ospf 1 area 0 – on R1
    ipv6 ospf 1 area 54 – on R4

    show ipv6 ospf int – to check what interfaces are participating in an OSPF on this router for IPv6.

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