From: Omkar Tambalkar (omkar.groupstudy@gmail.com)
Date: Mon Nov 03 2008 - 02:27:02 ARST
Type 3: Inter Area LSA
Type 4: ASBR Summary LSA
Type 5: External LSA
All these can be blocked by configuring the OSPF area as a totally stubby
area. After blocking all the above LSAs the routers in the totally stubby
area need a route to reach to other destinations out of the area and because
they cannot receive specific destination networks via the above blocked LSAs
which is why the ABR of the totally stubby area will inject the default
route, if not then the totally stubby area will be totally isolated from the
rest of the OSPF domain.
HTH - Omkar
On Sat, Nov 1, 2008 at 9:57 PM, Tolulope Ogunsina <togunsina@gmail.com>wrote:
> Totally stubby areas allow a default route from the ABR. To allow
> access to all other routers in the totally stubby area.
> Secondly you only need the no-summary option on the ABR.
>
> Regards,
>
> Tolulope
>
>
> On 11/2/08, Eric Leung <eric.lwc@gmail.com> wrote:
> > Hi Omar,
> >
> > "area 1 stub no-summary" will be the correct answer. The default route
> > generated is of type 3. This is to allow all routers in area 1 to route
> all
> > traffic external to Area 1 to the ABR (R1 in your case), this default
> route
> > is genereated automatically and unavoidable.
> >
> >
> http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094a74.shtml#stubandtotallystubareas
> >
> > HTH,
> > Eric.
> > 2008/11/2 omar parihuana <omar.parihuana@gmail.com>
> >
> >> Hi GS,
> >>
> >> I'm a bit confused. I have the follow task: Area 1 should not receive
> LSA
> >> Types 3, Types 4 and Types 5. so the answer is:
> >>
> >> in both routers:
> >>
> >> router ospf 1
> >> area 1 stub no-summ
> >>
> >> however, the routing table show:
> >>
> >> O*IA 0.0.0.0/0 [110/74] via 131.1.12.2, 00:14:56, Serial0/0.102
> >>
> >> and this default route is a LSA Type 3 in accordance to OSPF database:
> >>
> >> R1#sh ip ospf database
> >>
> >> Summary Net Link States (Area 1)
> >>
> >> Link ID ADV Router Age Seq# Checksum
> >> 0.0.0.0 22.2.2.2 932 0x80000003 0x0017FF
> >> R1#
> >>
> >> So I think that the answer is not exactly because there is a LSA Type 3
> >> (default route) anyway what will be the correct answer?
> >>
> >> Rgds.
> >>
> >> --
> >> Omar E.P.T
> >> -----------------
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> >
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> >
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>
> --
> Best Regards,
>
> Tolulope.
>
>
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