[c-nsp] OSPF NSSA Question

Dan Armstrong dan at beanfield.com
Sun Sep 12 17:26:18 EDT 2004


Thanks to everybody that replied.

I think I have a perfect solution.  

If I setup the interfaces on the distribution layer routers as ip ospf network 
point-to-multipoint non-broadcast

and set the access routers as  point-to-multipoint without the non-broadcast 
command 

I get exactly the behaviour I want.  The access routers all neighbour 
automatically, they all neighbour automatically with the distribution layer 
routers, but the 2 dist routers never neighbour!

Cool..

Can anybody think of why this might be crackheaded, or might break later on?

Dan.





On Saturday 11 September 2004 14:20, Zaheer Aziz wrote:
> At 05:36 PM 9/10/2004 -0400, Dan Armstrong wrote:
>
>
> Hi Dan,
>
> On any of the distribution routers apply this access-list on the incoming
> interface
>
> access-list 101 deny   ospf host 116.16.13.1 host 224.0.0.5
> access-list 101 permit ip any any <<<<<< or whatever
>
> 116.16.13.1  is interface access of the  OTHER dist router.
>
> This should prevent neighbor relationship bw the two. There are other
> methods like using secondary address etc etc but this should be the
> simplest.
>
> Hope this helps
> Zaheer
>
> >I have a question, that may seem rather silly.... but it is driving me
> > nuts.
> >
> >I have an NSSA area with a few access routers in it.  They are connected
> > via Ethernet to 2 distribution layer routers.  The dist routers are
> > advertising in a default route, and life is good.
> >
> >I would like to conserve IP addresses, and I was hoping to put the
> > interfaces on the access routers, and the corresponsing interfaces on the
> > distribution layer routers all in the same subnet - rather than make a
> > whackload of /30nets everywhere.
> >
> >My problem is that when I do that, the two distribution layer routers form
> > an adjacency with each other over the link%$#@#!!
> >
> >I realize that is "normal" behaviour... but it is not deseriable..
> >
> >Can I:
> >
> >-Explicitly force the two dist routers somehow not to form the adjacency?
> >-Do I just go head and make my whackload of /30nets, and chew up IPs?
> >
> >It seems to me that this much have come up before....
> >
> >Any thoughts are appreciated.
> >
> >Dan.
> >
> >
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