From: DAN DORTON (DHSTS68@xxxxxxxxxxxxxxx)
Date: Wed Dec 26 2001 - 11:33:56 GMT-3
I had a situation with OSPF to IGRP redistribution to which I had an
ISDN backup link that was in area 0 & was a different mask than the rest
of the network.
The IGRP router interface was a /24 & it reconized all the /24 routes &
the routes within the OSPF network at ABRs with a different mask I used
the area range command to summarize to a /24. I still could not get this
to work due to the fact that when the ISDN came up the /28 route for it
did not get to the IGRP network. Therefore all the routes that were in
the table that had to transit the ISDN link were inaccessable.
After trying many scenarios I came up with an idea. I could not see
this as being a problem in the lab since there was no static, or default
routes, but I thought I would get your opinion.
The network was 172.100.10.0/28. I need to get this into the IGRP
network which was a 172.100.100.0/24 network. I created a loopback with
the address of 172.100.10.17/28 & then created a summary address within
OSPF of 172.100.10.0/24. Then I redistributed connected & only allowed
this network with route-maps. Once the redistribution occured & the
loopback interface was not already in the OSPF process it injected the
172.100.10.0/24 summary route into the IGRP AS. Everything worked just
fine & dandy.
Anyone else used this method?
I kept seeing thing through this mailing list about using secondaries
to fix this issue, but I must not have understood correctly since I
could never make it work that way.
Thanks,
Dan
>>> "tom cheung" <tkc9789@hotmail.com> 12/21/01 01:20PM >>>
Ron,
The area range for area 0 only works on older IOS. I don't that works
on
12.1, which is IOS in the lab now.
Tom
>From: "Kirby, Ron" <Ron.Kirby@getronics.com>
>Reply-To: "Kirby, Ron" <Ron.Kirby@getronics.com>
>To: "'Thomas Larus'" <tlarus@mwc.edu>, ccielab@groupstudy.com
>Subject: RE: OSPF to IGRP redistrib - How to summarize area 0 routes?
>Date: Fri, 21 Dec 2001 12:33:30 -0500
>
>The "area range" command will summarize a backbone net into an IGRP
AS. I
>did a lab similar to this 2 days ago. The IGRP AS was a /24 and the
frame
>network, which was the ospf area 0 was a /28. I also had /32's from
some
>loopbacks that had to go into the IGRP AS as well. I played with
various
>ways to do it. First, I had a Class C network hanging off another
router,
>so I created a default route to that classful network on the
IGRP-only
>router and I could ping everything in the OSPF system, even though the
>frame
>and loopback addresses were not in the routing table. I suspect this
would
>not be acceptable though, as this is a "default-route", it just
doesn't use
>the quad-zero entry in the routing table, but it does work. Next I
added
>the "ip ospf network type" command to the loopbacks and used the
"area
>range" command at the redistribution point, summarizing the /28 to a
/24.
>The loopbacks appeared at the IGRP router as /24s, but not the /28s.
I had
>to add the null route to the config on the redistribution router (as
>explained by Doyle in V1) and then it worked fine, both the loopbacks
and
>the frame network (as a /24) was in the IGRP routing table. But is
that a
>technical no-no, as it involves a "static route"? If this is a no-no,
what
>else can you do to get /28s into an IGRP AS using a /24??
>
>Ron Kirby
>CCNP, MCSE, CNA
>Network Engineer
>Getronics, Houston ESC
>713-852-5567 / 832-256-5403
>ron.kirby@getronics.com
>
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>
>
>
>
>
>-----Original Message-----
>From: Thomas Larus [mailto:tlarus@mwc.edu]
>Sent: Friday, December 21, 2001 11:10 AM
>To: ccielab@groupstudy.com
>Subject: OSPF to IGRP redistrib - How to summarize area 0 routes?
>
>
>I am working on basic everyday OSPF to IGRP redistribution. I was
able
>to use area range for the routes I needed to get down to /24 to match
>the IGRP domain s mask. But what if the scenario had been set up
>differently, and I had had routes within area 0 that had to be
>summarized to /24 to be redist ed into IGRP? Area range summarizes
>non-backbone areas INTO area 0. Summary-address only works on routes
>redistributed INTO the OSPF domain. The experts all say that there
are
>two way to deal with the classless to classful redist problem
static
>routes and summarization. If it is stated that I cannot use static
>routes, and the routes I need to summarize are within area 0, what do
I
>do?
>
>I can design the network to make sure all the routes that need to be
>redistributed from OSPF to a classfull routing protocol are in an
area
>other than 0, but what if I am given the situation I have set out?
>
>A route-map comes to mind, but I don t see how I can summarize using
a
>route-map, although I can make it so that only routes with a certain
>mask get redistributed.
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