From: Mannan Venkatesan (venkat_m@xxxxxxx)
Date: Thu Apr 19 2001 - 15:25:22 GMT-3
Julie,
Thanks for the response. I tried it and found the following. I would like to
confirm whatever I understand is right. Let me re-draw my scenario.
I have used class B address, 170.100.0.0
I I/O O
------- r1----------r2-----------r3-------------
1.0/24 4.0/24 2.4/30 /29,/28,27 subnets
I configured everything without redistribution, worked fine. Then, I
configured redistribution from IGRP to OSPF on R2, worked as expected. Then
I typed 'summary address 170.100.2.0 255.255.255.0' under ospf process (for
OSPF -> IGRP redistribution) which created a summary address 170.100.2.0 -
>null 0 on R2 routing table. On R3 routing table it appeared as E2 route.
But note that I haven't configured OSPF -> IGRP redistribution yet.
So, the E2 route was inserted by OSPF process. It is not coming back from
IGRP because there was no OSPF -> IGRP redistribution. I had a impression
that the E2 route is because of route loop.
So, I can't filter that summary router on r2. If I do, OSPF -> IGRP red.
wouldn't work which is happening when I used distribution-list out.
Is it a normal behavior of OSPF? Or am I missing some OSPF basic?
Thanks,
Mannan
----- Original Message -----
From: "Connary, Julie Ann" <jconnary@cisco.com>
To: "Mannan Venkatesan" <venkat_m@ins.com>
Sent: Thursday, April 19, 2001 9:40 AM
Subject: Re: summary-address in ospf and redistribution
> Mannan,
>
> it is pratically impossible to tell from your diagram what your topology
> is. I am assuming that igrp is running between routers r1 and r2. R2 is
the
> re-distribution router and area 0 is between r2 and r3, area 1 is between
> r3 and r4. The OSPF area is variably subnetted of the Ip address
> 170.100.2.0 and 170.100.4.0? And the IGRP area is 170.100.1.0/24? So you
> are trying to summarize the 170.100.2.0 network to a class 24 boundary to
> redistribute into EIGRP? And why are you not redistributing OSPF into
> IGRP? I think this is part of your problem. Try that and let me know.
>
> Unfortunately the example at the bottom, upon closer inspection is
> backwards. I thinkthe two access-lists should be swapped. I edited this
> below.
>
> Julie Ann
>
>
> At 10:14 PM 4/18/2001 -0400, you wrote:
> >Hi,
> >I was trying this scenario. Have a question for you. Where did you use
> >route-map? When I used route-map on the redistribution router, the
summary
> >route( 170.100.2.0 ->null0) disappeared from the routing table and I
> >couldn't ping OSPF networks from IGRP router.
> >
> > IGRP IGRP/OSPF
> >Area 0 OSPF Area 1
>
-------------------R1------------------------R2---------------------------
R
> >3----------------------R4--
> > 170.100.1.0/24 170.100.4.0/25 170.100.2.4/30
> >/29, /28, /30 networks
> >
> >
> >R2 Config:
> >router ospf 10
> > summary-address 170.100.2.0 255.255.255.0
> > redistribute igrp 10 metric-type 1 subnets route-map sum
> > network 170.100.2.4 0.0.0.3 area 0
> >!
> >router igrp 10
> > network 170.100.0.0
> >!
> >no ip classless
> >access-list 1 permit 170.100.2.0 0.0.0.255
> >route-map sum deny 10
> > match ip address 1
> >!
> >route-map sum permit 20
> >!
> >
> >I could able to filter that E1 route on R3 by using distribution-list in.
> >But the OSPF database still had that E1 route which is the normal
behavior
> >of OSPF.
> >
> >I would like to filter it on the redistribution router. Any advice?
> >
> >Thanks,
> >Mannan
> >
> >
> >
> >
> >
> >----- Original Message -----
> >From: "Connary, Julie Ann" <jconnary@cisco.com>
> >To: <SherefMohamed@cdh.org>
> >Cc: <ccielab@groupstudy.com>; <nobody@groupstudy.com>
> >Sent: Tuesday, January 23, 2001 12:31 PM
> >Subject: Re: summary-address in ospf and redistribution
> >
> >
> >I tested a similar theory with route-maps and worked
> >like a champ.
> >Beware - the fatkid lab posted solution
> >(http://www.fatkid.com/html/501_expert_redistribution_-_ro.html)
> > does not use route-maps - and the posted routing tables - however
reflect
> >that route-map were used.
> >
> >Julie Ann
> >
> >At 09:55 AM 1/23/2001 -0600, SherefMohamed@cdh.org wrote:
> >
> > >You need to do mutual redistribution between OSPF and IGRP,
> > >the idea is to not allow IGRP send back to OSPF the summary address !
> > >Here is how I will do it:
> > >
> > >!
> > >router igrp 2
> > >..........
> > >distribute-list 11 out ospf --- key here is to distribute the
> > 172.10.2.0 subnet into igrp. Of course this example will only
>
> distribute the 172.10.2.0 subnet and
no
> others.
>
> > >..........
> > >!
> > >router ospf 1
> > >...........
> > >distribute-list 10 out igrp --- key here is not to redistibute it back
> > into OSPF.
> > >...........
> > >!
> > >
> > >access-list 10 deny 170.10.2.0 0.0.0.255
> > >access-list 10 permit 0.0.0.0 255.255.255.255
> > >!
> > >access-list 11 permit 172.10.2.0 0.0.0.255
> > >access-list 11 deny 0.0.0.0 255.255.255.255
> > >
> > >Please test it & tell me how it works !
> > >
> > >Thanks
> > >Sheref
> > >
> > >
> > >
> > >
> > >
> > >
> > > "Connary,
> > >
> > > Julie
> > > Ann" To: ccielab@groupstudy.com
> > >
> > > <jconnary@cis cc:
> > >
> > > co.com> Subject: summary-address
in
> > > ospf and redistribution
> > > Sent
> > > by:
> > >
> > > nobody@groups
> > >
> > > tudy.com
> > >
> > >
> > >
> > >
> > >
> > > 01/23/2001
> > >
> > > 08:37
> > > AM
> > >
> > > Please
> > >
> > > respond
> > > to
> > >
> > > "Connary,
> > >
> > > Julie
> > > Ann"
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >Hi All,
> > >
> > >I ran across a practice lab and another fat-kid lab that use the ospf
> > >summary-address to overcome
> > >vlsm to fsm issues when redistributing ospf into igrp:
> > >
> > >
> > >
> > >situation: The ospf connected interface has a longer mask than the IGRP
> > >connected interface.
> > > area-range does not work because it is on the
same
> > >router.
> > >
> > > The Fatkid lab - expert redistribution - solves this with
a
> > >summary-address.
> > >
> > >Question - does this not inject E2 routes back into your OSPF domain?
> > >
> > >
> > >OSPF area 2
> > >170.10.128.4 - 255.255.255.192
> > >|
> > >|
> > >|
> > >R4 -----------IGRP - 170.10.2.4 255.255.255.0
> > >
> > >To redistribute the ospf interface into IGRP a summary-address is
> > >used: summary-address 170.10.128.0 255.255.255.0
> > >
> > >But then in the ospf domain you get an E2 route to 170.10.128.0 in
your
> > >ospf domain.
> > >
> > >So how do you prevent this E2 route into OSPF - can you filter it?
> > >
> > >Thoughts?
> > >
> > >remember - no static, no default.
> > >
> > >Julie Ann
> > >
> > >
> > >
> > >
> >
>------------------------------------------------------------------------
> > > Julie Ann Connary
> > > | | Network Consulting Engineer
> > > ||| ||| Federal Support Program
> > > .|||||. .|||||. 13635 Dulles Technology
Drive,
> > >Herndon VA 20171
> > > .:|||||||||:.:|||||||||:. Pager:
> >1-888-642-0551
> > > c i s c o S y s t e m s Email: jconnary@cisco.com
> > >
> >
>------------------------------------------------------------------------
> >------------------------------------------------------------------------
> > Julie Ann Connary
> > | | Network Consulting Engineer
> > ||| ||| Federal Support Program
> > .|||||. .|||||. 13635 Dulles Technology
Drive,
> >Herndon VA 20171
> > .:|||||||||:.:|||||||||:. Pager: 1-888-642-0551
> > c i s c o S y s t e m s Email: jconnary@cisco.com
> >
> >------------------------------------------------------------------------
> ------------------------------------------------------------------------
> Julie Ann Connary
> | | Network Consulting Engineer
> ||| ||| Federal Support Program
> .|||||. .|||||. 13635 Dulles Technology Drive,
> Herndon VA 20171
> .:|||||||||:.:|||||||||:. Pager: 1-888-642-0551
> c i s c o S y s t e m s Email: jconnary@cisco.com
>
> ------------------------------------------------------------------------
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