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  • 1.  Redistribution routes between two ospf areas

    Posted 08-16-2023 13:41

    Hello Experts,

    I need to know how can we redistribute between different areas in OSPF,

    below is the current Cisco configuration and I need to swap this device to Juniper,

    I know there is an export in Juniper to do the redistribute, and in Juniper we can add just one router ID and there is no process number for OSPF as Cisco,

    my inquiry is how can I do the below redistribute after swapping to Juniper

    router ospf 10
     router-id 1.1.1.1
     redistribute ospf 1 metric 100 subnets
    !
    router ospf 1
     router-id 2.2.2.2
     redistribute ospf 10 metric 100 subnets
    !



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    SUDQI AL-IMAM
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  • 2.  RE: Redistribution routes between two ospf areas

    Posted 08-16-2023 14:41

    Hello
    You could build two routing instances, each one with its own OSPF process and associated network interfaces.

    Then I think you can move routes from one instance to the other and viceversa. One that comes to my mind is to connect both instances physically with a common link, this link joining interfaces belonging to each instance. In that link you can peer both OSPF processes on a common area 0.0.0.0

    In JUNOS there are tons of techniques to achieve what you want (routing instances of type "forwarding", RIB groups, etc etc), but it would take me a while to find something better than my first idea. Someone else will surely suggest a better approach to the solution to your need.

    regards, Rogelio




  • 3.  RE: Redistribution routes between two ospf areas

    Posted 08-16-2023 14:50

    I suggested this under the assumption you do not want to filter the knowledge of routes between the OSPF processes, since your IOS "redistribute" commands do not include any route-maps for the purpose of filtering. 

    I am pretty sure someone else will provide a much much better suggestion than mine. I just suggested a very basic idea that could be used as a workaround until a better idea is published here. For the time being, two routing instances of type "virtual-router", each one with its own OSPF process and interfaces, and a common link between both instances should do it. I will not earn a JNCIA badge for it :o)

    regards, Rogelio




  • 4.  RE: Redistribution routes between two ospf areas

    Posted 08-17-2023 05:13

    Thank you Ralvez,

    I appreciate your suggestion, but two router instances are not the recommended solution, I just need to configure different areas and share the routes between them



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    SUDQI AL-IMAM
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  • 5.  RE: Redistribution routes between two ospf areas

    Posted 08-17-2023 09:16

    As posted by ralvez ..

    Normal / best practice would be to create Area 0 on one of your routers as an ABR.

     https://networklessons.com/ospf/ospf-lsa-types-explained  . Shows Cisco  stuff.

    Juniper ABR    https://www.juniper.net/documentation/us/en/software/junos/ospf/topics/topic-map/configuring-ospf-route-control.html

    If you cannot do that . 

    Sounds like you need to user RIB to do your redistribute acl 

    https://www.juniper.net/documentation/us/en/software/junos/ospf/topics/topic-map/configuring-ospf-routing-instances.html




  • 6.  RE: Redistribution routes between two ospf areas

    Posted 08-17-2023 09:40

    Hello:

    Unless I misunderstood the question, your OSPF code says that you do want two different processes that do not talk to each other except by redistribution; IMHO that must be done with routing-instances in JUNOS. If you can get rid of the two different processes, then a plain OSPF configuration with an ABR will do it.

    regards, Rogelio