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OSPF path fixing

DevilWAHDevilWAH Member Posts: 2,997 ■■■■■■■■□□
In the digram below all the routers are attached to a shared segment.

at the moment all know about the connected networks via OSPF and would currently talk directly to each other over a single hop.

what I want to achive is if a user in network 192.168.1.0 sends a packet to 192.168.4.0. then rather than CAB1 user CAB4 ip as the next hope. it uses the core as the next hope address. (IE all traffic gets routed by the Core, rather than just getting switchs through it).

I know I can achive this with route maps, but I was trying to achive it with costs, by making the core links to the CABS low cost, but the links between the cabs high cost. So OSPF would choses the double hop as the prefered route.

But I can't get this to work, any suggestions how I might achive this.

I want all traffic routed by the central CORE as all traffic needs to be filtered by the same rule sets, And as the central router is a beefy beast and the traffic from each CAB being low I am not worried to much about any proformance hits I might take.
  • If you can't explain it simply, you don't understand it well enough. Albert Einstein
  • An arrow can only be shot by pulling it backward. So when life is dragging you back with difficulties. It means that its going to launch you into something great. So just focus and keep aiming.

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    networker050184networker050184 Mod Posts: 11,962 Mod
    I'm not sure what you are getting at here. Are all the routers neighbors? If so they should route directly to each other by default. Can you give us some more information on this?
    An expert is a man who has made all the mistakes which can be made.
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    DevilWAHDevilWAH Member Posts: 2,997 ■■■■■■■■□□
    yes all Routers are neighbour,

    (I have just notices I miss typed the attached networks, they should be 192.168.1,2,3,4.0 /24)

    Take CAB1, it's current routing table is

    192.168.1.0 /24 directly connected
    192.168.2.0/24 nexthop 10.0.0.3
    192.168.3.0/24 nexthop 10.0.0.4
    192.168.4.0/24 nexthop 10.0.0.5

    what I want to see is
    192.168.2.0/24 nexthop 10.0.0.1
    192.168.3.0/24 nexthop 10.0.0.1
    192.168.4.0/24 nexthop 10.0.0.1

    Ie. I don't want them to route directly to each other, but hop though the core.

    Now I know this may not be a normal way to do it, or even a best practice way. But I just want to know if its possible, and how you would set it up to do this.

    route maps are one way, but i was wondering if you can do it by costs.
    • If you can't explain it simply, you don't understand it well enough. Albert Einstein
    • An arrow can only be shot by pulling it backward. So when life is dragging you back with difficulties. It means that its going to launch you into something great. So just focus and keep aiming.
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    networker050184networker050184 Mod Posts: 11,962 Mod
    Ok sorry I was thinking you were trying to do it the other way. You can use point to multipoint non broadcast and statically define neighbors with cost. That way you don't have to mess with route maps or anything and the fail over is automatic.
    An expert is a man who has made all the mistakes which can be made.
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    DevilWAHDevilWAH Member Posts: 2,997 ■■■■■■■■□□
    LOL how ironic I am currently watching the CCNP CBT nuggets "understanding network types" video.

    Which is going through point to multi point and thinking "I wonder if this is what I am looking for...."

    Cheers for the conformation. I think I am going to turn my company site in to my test lab for OSPF. I have to implement a site wide routing protocol and its a choice between EIGRP and OSPF. (may possible play with it all on a actual test lab though before the real thing ;) )
    • If you can't explain it simply, you don't understand it well enough. Albert Einstein
    • An arrow can only be shot by pulling it backward. So when life is dragging you back with difficulties. It means that its going to launch you into something great. So just focus and keep aiming.
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