From: cebuano (cebu2ccie@cox.net)
Date: Sat Feb 22 2003 - 00:04:26 GMT-3
Hunt,
You are forgetting the fundamental reason for having areas in OSPF. Just
like the saying "all roads lead to Rome", All networks get funneled into
Area0, well, initially. Again check Doyle or John Moy's OSPF to get an
understanding of why these "non-normal" areas were created in the first
place. This will answer your question.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Bill Cooley
Sent: Friday, February 21, 2003 4:19 PM
To: Carlos; Hunt Lee
Cc: ccielab@groupstudy.com
Subject: Re: IBGP redistribution mystery
This may be some kind of bug. According to:
http://www.cisco.com/en/US/tech/tk648/tk365/technologies_tech_note09186a
0080094a88.shtml#topic1
"There are situations where there is no need to inject
external routes into the NSSA as type 7. This
situation usually occurs when an ASBR is also an NSSA
ABR. When redistribution takes place in this scenario,
the router generates type 5 as well as type 7 LSAs."
Bill C.
--- Carlos <cchorao@xtra.co.nz> wrote:
> Hunt ,
>
> Based on my experiences so far the answer to your
> question would be no. The
> abr(r5)
> does type 7 to 5 translation , not 5 to 7 i.e
> external routes originating
> on R6 will reach R5 and R5 will pass these into the
> backbone, however type
> 5's arriving at R5 through the backbone are never
> into the nssa area and so
> r6 should never see these routes.
>
>
>
>
>
> Carlos
> Telecom New Zealand - Advanced Solutions Group :
> Network Design and Security
> ----- Original Message -----
> From: "Hunt Lee" <huntl@webcentral.com.au>
> To: "'Carlos'" <cchorao@xtra.co.nz>
> Cc: <ccielab@groupstudy.com>
> Sent: Friday, February 21, 2003 5:59 PM
> Subject: RE: IBGP redistribution mystery
>
>
> > Hi Carlo,
> >
> > That's exactly my point... if I redistribute BGP
> into OSPF at R5,
> shouldn't
> > the BGP route get into the OSPF as LSA Type 7??
> >
> > Hunt
> >
> >
> > -----Original Message-----
> > From: Carlos [mailto:cchorao@xtra.co.nz]
> > Sent: Friday, 21 February 2003 1:05 PM
> > To: Hunt Lee
> > Cc: ccielab@groupstudy.com
> > Subject: Re: IBGP redistribution mystery
> >
> >
> > Hunt,
> >
> > The purpose of NSSA is to enable the area to
> have stub capablities ( i.e
> > no lsa 5's in the area) but still allowing into
> originate external routes
> > (as type 7 lsa's). A default route must be
> injected at the abr if the
> > routers inside the nssa need to reach type 5 lsa's
> destinations.
> >
> >
> > Tx
> > Carlos
> > Telecom New Zealand - Advanced Solutions Group :
> Network Design and
> Security
> > ----- Original Message -----
> > From: "Hunt Lee" <huntl@webcentral.com.au>
> > To: "'Carlos'" <cchorao@xtra.co.nz>
> > Cc: <ccielab@groupstudy.com>
> > Sent: Friday, February 21, 2003 3:28 PM
> > Subject: RE: IBGP redistribution mystery
> >
> >
> > > Correctly me if I'm wrong, but I thought the
> whole point of NSSA is to
> > allow
> > > "external routes" to get in while having Stub
> area capability at the
> same
> > > time???
> > >
> > > Or am I completely off??
> > >
> > > Best Regards,
> > > Hunt Lee
> > >
> > >
> > > -----Original Message-----
> > > From: Carlos [mailto:cchorao@xtra.co.nz]
> > > Sent: Friday, 21 February 2003 10:02 AM
> > > To: Hunt Lee; ccielab@groupstudy.com
> > > Subject: Re: IBGP redistribution mystery
> > >
> > >
> > > Hunt,
> > >
> > > if r5-r6 is a nssa , then no type 5 lsa enter
> the area. Net
> 200.200.200.0
> > is
> > > a type 5. Why should it appear on R6 ?
> > >
> > >
> > >
> > >
> > > Carlos
> > > Telecom New Zealand - Advanced Solutions Group :
> Network Design and
> > Security
> > > ----- Original Message -----
> > > From: "Hunt Lee" <ciscoforme3@yahoo.com.au>
> > > To: <ccielab@groupstudy.com>
> > > Sent: Thursday, February 20, 2003 2:35 AM
> > > Subject: IBGP redistribution mystery
> > >
> > >
> > > > Hi Group,
> > > >
> > > > Just got a funny stuff. Remember how they
> said that with "bgp
> > > > redistribute-internal", one can then
> redistribute IBGP routes into IGP
> > > (like OSPF).
> > > > Well... I just got a wierd one, perhaps some
> of you can try. Here is
> > the
> > > topology
> > > >
> > > > r4---EBGP---r3---OSPF Frame---r1---OSPF
> Frame---r5---NSSA---r6
> > > >
> > > > So now, what I did, I put a "redistribute bgp
> 3" at r5 under OSPF
> > process,
> > > but the
> > > > IBGP route just doesn't want to get into the
> NSSA area.
> > > >
> > > > router ospf 1
> > > > log-adjacency-changes
> > > > area 4 authentication
> > > > area 4 nssa default-information-originate
> > > > area 4 default-cost 20
> > > > redistribute bgp 3 metric 20 subnets
> > > > network 10.10.1.5 0.0.0.0 area 0
> > > > network 11.1.1.5 0.0.0.0 area 4
> > > >
> > > > router bgp 3
> > > > no synchronization
> > > > bgp redistribute-internal
> > > > bgp log-neighbor-changes
> > > > neighbor 10.10.1.1 remote-as 3
> > > >
> > > >
> > > > Here is the routing table of r5
> > > >
> > > > B 200.200.200.0/24 [200/0] via 10.10.1.3,
> 03:33:03
> > > > 137.20.0.0/24 is subnetted, 1 subnets
> > > > O IA 137.20.20.0 [110/138] via 10.10.1.1,
> 00:00:25, Serial0
> > > > 22.0.0.0/24 is subnetted, 1 subnets
> > > > B 22.1.1.0 [200/0] via 10.20.1.1,
> 00:51:42
> > > > 10.0.0.0/8 is variably subnetted, 11
> subnets, 4 masks
> > > > O 10.10.1.1/32 [110/64] via 10.10.1.1,
> 00:00:26, Serial0
> > > > C 10.10.0.0/16 is directly connected,
> Serial0
> > > > O 10.10.1.3/32 [110/128] via 10.10.1.1,
> 00:00:26, Serial0
> > > > O IA 10.3.1.1/32 [110/129] via 10.10.1.1,
> 00:00:27, Serial0
> > > > O IA 10.1.0.0/17 [110/65] via 10.10.1.1,
> 00:00:27, Serial0
> > > > O IA 10.4.0.0/16 [110/202] via 10.10.1.1,
> 00:00:27, Serial0
> > > > O IA 10.20.0.0/16 [110/128] via 10.10.1.1,
> 00:00:27, Serial0
> > > > O IA 10.44.1.1/32 [110/193] via 10.10.1.1,
> 00:00:28, Serial0
> > > > B 10.44.0.0/16 [200/0] via 10.10.1.3,
> 03:33:05
> > > > O IA 10.34.0.0/16 [110/192] via 10.10.1.1,
> 00:00:28, Serial0
> > > > O IA 10.33.1.0/25 [110/129] via 10.10.1.1,
> 00:00:28, Serial0
> > > > 11.0.0.0/16 is subnetted, 4 subnets
> > > > O N1 11.3.0.0 [110/21] via 11.1.1.6,
> 00:00:28, Ethernet0
> > > > O N1 11.2.0.0 [110/21] via 11.1.1.6,
> 00:00:28, Ethernet0
> > > > C 11.1.0.0 is directly connected,
> Ethernet0
> > > > O N1 11.4.0.0 [110/21] via 11.1.1.6,
> 00:00:28, Ethernet0
> > > > 30.0.0.0/24 is subnetted, 1 subnets
> > > > B 30.1.2.0 [200/0] via 10.10.1.3,
> 03:33:05
> > > > O*E2 0.0.0.0/0 [110/1] via 10.10.1.1,
> 00:00:28, Serial0
> > > > R5#
>
=== message truncated ===
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