From: Michel GASPARD (mgaspard@xxxxxxxxx)
Date: Fri Apr 20 2001 - 03:29:13 GMT-3
Mannan,
1) According to Doyle (p723-724), OSPF "summary-address" can only be
used for summarization of external routes, in the ASBR, INTO the OSPF
process.
2) From:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/np1_r/1r
prt1/1rospf.htm#xtocid677242
we have:
"
Using this command for OSPF causes an OSPF autonomous system boundary
router (ASBR) to advertise one external route as an aggregate for all
redistributed routes that are covered by the address. For OSPF, this
command summarizes only routes from other routing protocols that are
being redistributed into OSPF.
"
3) Well, that is the official version. Some people claims it is also
working the other way around (OSPF => other). I will test that this
afternoon.
4) A quick check on groupstudy's archive with "summary-address" give you
PLENTY of more stuff to read!!
Regards,
Michel
Mannan Venkatesan wrote:
>
> 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
> >
> > ------------------------------------------------------------------------
> **Please read:http://www.groupstudy.com/list/posting.html
**Please read:http://www.groupstudy.com/list/posting.html
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