From: Sila Moni (silamoni@yahoo.com)
Date: Sun Jun 26 2005 - 22:55:30 GMT-3
Thanks George. I was like 'oopsie' when I saw it. :)
So in this case R2 is an ASBR since it connects to
external net. That explains why you used
summary-address. Now that you got me thinking, I've
one question involving GRE (expanding upon Tim's
topology a bit).
R4 (area 2) R1 (nssa area 1) R2 (area 0) R3
We have a disconnected area 2 separated by nssa. In
this case, you'd need to create a GRE tunnel. When I
last try to lab it out, I'd recursive route problem
when I used ip unnumber.
a) How do I avoid recurvise route?
b) Replace area 2 with area 0. Do you still configure
the tunnel the same way?
TIA,
Sila
--- George Cassels <glcassels3@nc.rr.com> wrote:
> Sila,
>
> Take a look at my response to Tim...I used the
> summary-address
> command and it aggregated the routes going to
> another ospf area 0
> router.
>
> George
>
> -----Original Message-----
> From: nobody@groupstudy.com
> [mailto:nobody@groupstudy.com] On Behalf Of
> Sila Moni
> Sent: Sunday, June 26, 2005 7:31 PM
> To: ccie2be; Group Study
> Subject: Re: using nssa and area X range together
>
> You can't summarize external routes (I don't have a
> rack to lab it out to confirm). Since R2 has only
> one
> exit point, you can use LSA 3 filter to deny all
> routes except for the default prefix. Example:
>
> ip prefix-list LSA-FILTER deny x.x.x.x/24
> ip prefix-list LSA-FILTER permit 0.0.0.0/0 le 32
> !
> router ospf 1
> area 1 filter-list prefix LSA-FILTER in
>
>
> --- ccie2be <ccie2be@nyc.rr.com> wrote:
>
> > Hi guys,
> >
> > This is an interesting scenario - at least I
> hadn't
> > thought much about this
> > previously.
> >
> > Let's say you have this topology:
> >
> > IGP R1 nssa R2 area 0 R3
> >
> >
> > R1 is redist routes from another IGP into OSPF.
> Can
> > I use the area X range
> > command on R2 to summarize routes learned from the
> > IGP redist into the nssa
> > area so that the backbone doesn't have all those
> > specific routes from the
> > other routing protocol?
> >
> >
> > And, more generally, do I need to be concerned
> about
> > any restrictions on
> > using the area X range command to summarize routes
> > into the backbone area
> > depending upon what type of stub area is
> configured?
> >
> > What I find interesting about this scenario is
> that
> > typically when I think
> > about what type of stub area to configure, I'm
> > concerned about what routes
> > are advertised into the stub area from the
> backbone.
> >
> > In this scenario, it's just the opposite. Here
> the
> > concern is what routes
> > area advertised from the stub area into the
> backbone
> > area.
> >
> > (I don't have access to any routers at the moment
> to
> > lab this up.
> >
> > TIA, Tim
> >
> >
>
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