From: Toh Soon, Lim (tohsoon28@gmail.com)
Date: Sun Aug 26 2007 - 16:02:31 ART
Hi Shine,
Noted with thanks.
Is there a workaround to this? I mean, the ability to summarize inter-area
routes on the ABR into another area using the "area range" command?
In my case if R4 learns 1000 inter-area routes and only 10 intra-area
routes, and all of them can be summarized by a single summary route, then
only the 10 intra-area routes are suppressed from entering Area 4 while the
1000 inter-area routes will "leak" into Area 4. Maybe I can make Area 4 a
totally stubby area since it's connected to only one ABR (R4).
Kindly comment.
Thank you.
B.Rgds,
Lim TS
On 8/27/07, CCIE 19999 <ccie@iprimus.com.au> wrote:
>
> Lim,
>
> You are telling the router to summarise the routes originated from area 0
> in
> the command. SO the router is doing exactly the same. It summarizes the
> routes originated in Area 0.
>
> HTH,
> Shine
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Toh
> Soon, Lim
> Sent: Monday, 27 August 2007 12:35 AM
> To: Serhat Aslan
> Cc: Cisco certification
> Subject: Re: OSPF "area range" command summarizes only intra-area routes?
>
> Hi Serhat,
>
> I'm sorry I don't fully understand your points.
>
> Without any area summarization, routers in Area 4 will learn all the
> 200.0.0.x/32 routes as inter-area routes.
>
> I want to summarize all these host routes so that routers in Area 4 only
> see
> 200.0.0.0/24. I did it on the ABR (R4) using the "area 0 range 200.0.0.0
> 255.255.255.0" command.
>
> However, Area 4 still sees 200.0.0.9/32. Why? As far as R4 is concerned,
> the
> 200.0.0.9/32 is an inter-area route whereas the other 200.0.0.x/32 are
> intra-area routes.
>
> Appreciate your further advice.
>
>
> Thank you.
>
> B.Rgds,
> Lim TS
>
>
> On 8/26/07, Serhat Aslan <serhatworks@gmail.com> wrote:
> >
> > Hi Toh,
> > You made a wrong summarization. The steps of the summarizations are:
> > 0. The areas must be originated with the specified ABR. This means
> > intra-area routes.
> > 1. Choosing an Area, (the routes must be originated with the same area)
> > "area-range X"
> > 2. Area Routes Aggregation, (IP subnet mask supernetting)
> >
> > You forgot to consider step1.
> >
> > Serhat Aslan
> >
> >
> > On 8/26/07, Toh Soon, Lim <tohsoon28@gmail.com> wrote:
> >
> > > Hi Group,
> > >
> > > R4 is an ABR connected to Area 0 and Area 4. It learns the following
> > > routes
> > > in Area 0:
> > >
> > > Intra-area:
> > > 200.0.0.2/32
> > > 200.0.0.5/32
> > > 200.0.0.6/32
> > >
> > > Inter-area:
> > > 200.0.0.9/32
> > >
> > > I'm trying to summarize the above routes into Area 4, as follows:
> > >
> > > !
> > > router ospf 1
> > > area 0 range 200.0.0.0 255.255.255.0
> > > !
> > >
> > > Routers in Area 4 see the summary address 200.0.0.0/24. All component
> > > routes
> > > are suppressed except for 200.0.0.9/32 which "leaks" into Area 4. E.g.
> > >
> > > O IA 200.0.0.9/32 [110/784] via 192.168.40.1, 00:21:02,
> > > FastEthernet0/0
> > > O IA 200.0.0.0/24 [110/2] via 192.168.40.1, 00:17:49,
> > > FastEthernet0/0
> > >
> > >
> > > I suspect the "area range" command only summarizes intra-area routes.
> > > Can
> > > anyone clarify this? I might be missing something here.
> > >
> > >
> > > Thank you.
> > >
> > > B.Rgds,
> > > Lim TS
> > >
> > >
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