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Adding an AS Border router to area

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  • 1.  Adding an AS Border router to area

    Posted 05-06-2020 14:15

    I am still learning the ins and outs of the routing world and I have a question regarding ospf. Our network has 3 AS Border routers in ospf area and I would like to add a fouth one to that area. Am I right in thinking that adding the router should not cause service interruptions? The new router does not have any services built on it yet, I just want to get it added into area then build services on to it later. I have added new areas with edge routers before with no impact but since this is adding a router into an established area I wanted to gather information so I can have a little insight on what to expect. Thanks you.

  • 2.  RE: Adding an AS Border router to area

    Posted 05-06-2020 14:22

    Hi ,




    In this scenarios, i would overload the router till i add all the services to it then unoverload the router.

    Otherwise also it should not impact the traffic  with out overload as well. But i would prefer  safer approach like this one.





  • 3.  RE: Adding an AS Border router to area
    Best Answer

    Posted 05-06-2020 15:39

    Hi WadeH,  


    In a healthy system OS, it won't cause any issue because of the ability called the backbone area, has a special function as support LSA type 5 as part of its database. Now, the backbone itself does not have any ABRs. The backbone distributes routing information between areas. The backbone is simply another area, so the terminology and rules of areas apply: a routing device that is directly connected to the backbone is an internal router on the backbone.  


    continue as the definition of ASBR router.  


    AS Boundary Routers

    They advertise externally learned routes throughout the OSPF AS. Depending on the location of the AS boundary router in the network, it can be an ABR, a backbone router, or an internal router (with the exception of stub areas). 


    ref: https://www.juniper.net/documentation/en_US/junos/topics/topic-map/configuring-ospf-areas.html#id-11658562 


    I hope this helps! if you think the above info will clear your query please mark as solve!