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VRF Lite

Written by Rene Molenaar on . Posted in MPLS

Scenario:

You are running a small ISP on a tropical location somewhere in the pacific, recently two new customers have arrived and they both have 2 sites to connect. There's a headquarters (HQ) and a branch office and they want to use OSPF as the routing protocol. One of the problems you are facing is that both customers are using the same IP addressing scheme and it's impossible to change this. You also have to make sure that there is NO connectivity between the two companies. You believe vrf might be the solution to your problems...if you are able to pull this off you'll be rewarded with an infinite amount of grapes and melons from your customers...time to work!

Goal:

  • All IP addresses on the customer routers have been preconfigured for you.
  • You are not allowed to change the IP addressing scheme in this topology.
  • Configure the ISP router so you can ping router MelonHQ and MelonBranch.
  • Configure the ISP router so you can ping router GrapeHQ and GrapeBranch.
  • Configure OSPF Area 0 on router ISP, MelonHQ and MelonBranch, advertise all networks.
  • Configure OSPF Area 0 on router ISP, GrapeHQ and GrapeBranch, advertise all networks.
  • Router MelonHQ and MelonBranch should see each other's loopback networks.
  • Router GrapeHQ and GrapeBranch should see each other's loopback networks.
  • The Melon and Grape routers should NOT see each others routes and there should be no connectivity between them.

IOS:

c3640-jk9s-mz.124-16.bin

Topology:

VRF Lite

Video Solution:

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Comments (13)

  • avatar
    talaltk
    2010-12-21 16:10:38

    ok so i think its working. i created 2 diff vrf's for melon and grape. inserted the command ip vrf forwarding "vrf name" in the interface pointing towards the customer. defined ospf area 0 in each vrf. and the way i can tell that each vrf cannot see the other is thru show ip route vrf "name". in each name i c the same ip addresses but thru diff interfaces.

  • avatar
    bdk907
    2011-03-04 09:15:17

    In the pic above, the branch offices IPs are x.x.23.x when in the GNS config they are x.x.13.x. Had me for a loop because I was configuring via the above image and not the GNS3 drawing.

    Good lab, was able to complete it without having to look at commands....

    -bdk

  • avatar
    ReneMolenaar
    2011-03-14 14:38:26

    @Talal seems right to me, you create multiple vrfs and with the "show ip route vrf" command you can see the different routing tables.

    @BDK thanks for letting me know, just changed the picture.

  • avatar
    greatidea
    2011-07-14 16:51:21

    Hi Rene,

    This is the coolest LAB I've ever done so fast. Much much easier than it seems. Flawlessly executed.
    Great work and thanks

  • avatar
    ReneMolenaar
    2011-07-15 13:41:07

    Thanks Nikhil I'm glad you like it 8)

  • avatar
    ReneMolenaar
    2011-09-06 12:32:52

    Hi Mauro,

    This problem with OSPF is normal. Your loopback has an IP address but when it's not in the same VRF as your OSPF process it cannot be used for the router-ID. VRFs are pretty much the same as VLANs but on a layer 3 level.

    Rene

  • avatar
    Mauro1980
    2011-08-17 07:57:27

    After configured the various router ip ospf x process vrf forwaring x. They did made adjacency. After : SP#sh ip ospf neighbor
    &#xOS;PF: Router process 3 is not running, please configure a router-id
    although i'had used l0 interfaces. Solved using under every process manual conf
    router-id process L0 ip address

    Ty .

  • avatar
    dyowhel24
    2011-11-08 22:30:10

    This is so cool... 2 thumbs up... Great job Rene Molenaar!!! ;D

  • avatar
    ReneMolenaar
    2011-11-10 16:37:52

    Thanks glad to hear you like it ;D

  • avatar
    ReneMolenaar
    2012-08-24 14:45:06

    Thank you too for your message :)

  • avatar
    jarek
    2012-10-23 07:48:38

    Hi Rene,

    Thank you for this LAB, very nice and easy to understand the basic concept.

    Regards,
    Jarek

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