From: P729 (p729@xxxxxxx)
Date: Sat Jun 29 2002 - 15:27:23 GMT-3
David,
I think you've got it. Making area 1 an NSSA would cause the external RIP
domain to be advertised via type 7 LSAs throughout area 1. Using
'summary-address not-advertise' on R2 would allow you to control which type
7s are translated into type 5s to be flooded throughout the rest of the OSPF
AS.
Regards,
Mas Kato
https://ecardfile.com/id/mkato
----- Original Message -----
From: "David Ham" <ccieau@hotmail.com>
To: <franjime@cisco.com>; <peter@whittle-systems.demon.co.uk>;
<ccielab@groupstudy.com>
Sent: Saturday, June 29, 2002 8:18 AM
Subject: RE: OSPF route filtering teaser
> Frank,
>
> Could you pls bit more detail. I used nssa with summary-address
> not-advertise, it works great. But not sure about 2 ospf processes.
>
> Regards,
>
> David Ham
>
>
> >From: "Frank Jimenez" <franjime@cisco.com>
> >Reply-To: "Frank Jimenez" <franjime@cisco.com>
> >To: "'Peter Whittle'" <peter@whittle-systems.demon.co.uk>,
"'CCIELab
> > Studygroup'" <ccielab@groupstudy.com>
> >Subject: RE: OSPF route filtering teaser
> >Date: Fri, 28 Jun 2002 17:30:07 -0500
> >
> >Are we allowed to have two different OSPF processes running? If so, we
> >can run two different OSPF processes and redistribute between the R2/R3
> >process and the R3/R4 process.
> >
> >Frank Jimenez, CCIE #5738
> >franjime@cisco.com
> >
> >-----Original Message-----
> >From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> >Peter Whittle
> >Sent: Friday, June 28, 2002 3:11 PM
> >To: CCIELab Studygroup
> >Subject: OSPF route filtering teaser
> >
> >
> >Selectively blocking OSPF routes between areas
> >----------------------------------------------
> >
> >I would like to pose a simple scenario to the group.
> >
> >There are 4 routers R1 .. R4
> >
> >R1 is injecting routes into RIPv2 say 10.1.0.0/16
> >
> >R2 is running RIPv2 on e0, it is also connected by e1 to OSPF Area 1 and
> >must inject the routes learnt from RIP into AREA 1. There are other
> >routers also connected to the ethernet segment in Area 1 again running
> >OSPF. The routes injected by R2 into area 1 must be visible to these
> >routers via OSPF.
> >
> >R3 has 2 ethernet interfaces e0 in OSPF Area 0, and e1 in OSPF Area 1.
> >It must see the RIP routes injected into OSPF by R2 (ie 10.1.0.0/16).
> >
> >R4 in connected to the ethernet in Area 0 and is also running OSPF and
> >is outside of your control.
> >
> >STOP the RIP routes that were injected by R2 from being seen in Area 0.
> >(i.e. block the 10.1.0.0/16 route)
> >
> >You may only program routers R2, & R3 to achieve this.
> >
> >
> >Any thoughts, ideas, solutions?
> >
> >
> >I have one solution in mind but it is not very elegant. I will share
> >this next week when you have had time to think about the problem.
> >
> >
> >------------
> >
> >A distribute-list applied to R3, an ABR, will of course not work. (When
> >the 10.1 route reaches R3 it is in an LSA. If we apply the distribute-
> >list x in, it will only block the route going into R3's routing table,
> >it will not prevent the LSA from being sent on to R4. We are not
> >permitted to change the other routers in Area 0 so we can not use the
> >conventional approach of applying the distribute-list x in to each of
> >the routers in Area 0.
> >
> >If we apply a distribute-list x out to the ABR it will again have no
> >impact on the LSA advertising the 10.1 route into Area 0.)
> >
> >==========================
> >
> >May enlightenment be yours.
> >
> >Peter
> >
> >--
> >Peter Whittle
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