From: Mas Kato (tealp729@xxxxxxxx)
Date: Fri May 11 2001 - 20:46:27 GMT-3
Thanks Louie Kouncar, Johnny Dedon, et. al.,
I've seen your suggestions before, but have never gotten them to work
until now. I've always filtered during mutual redistribution as Johnny
describes in another post but didn't realize that always broke my
'summary-address' hack.
Situation, step-by-step on ASBR:
-'summary-address' for OSPF/28 routes to /24
-OSPF/28 mutual redist. with IGRP/24 (null0 routes installed,
unreachable in IGRP)
-IGRP default metric specified (routes now reachable in IGRP)
-Filter redist. to only allow IGRP-originated routes into OSPF (no null0
routes)
-Redist. conn., filter to allow only desired OSPF networks (null0 routes
back, but /24 E2 routes into the area alongside the corresponding /28
internal routes)
-Tried the last step on an internal OSPF router to summarize a /28
loopback and it too introduces a null0 route and injects a /24 E2 into
the area (again, alongside the corresponding /28 internal route). I do
not believe this worked when I was running 12.1(7) until I took the
loopback out of the area.
Has anybody seen anything resembling this behavior with other versions
of IOS?
Regards,
Mas Kato
-----Original Message-----
From: Mas Kato [mailto:tealp729@home.com]
Sent: Friday, May 11, 2001 3:11 PM
To: 'CCIELAB'
Subject: OSPF summary-address--The beat goes on...
(edited)
Manuel,
Thank you! Now we're getting somewhere! But the plot thickens...
I back-dated my lab to 12.0(17) and pasted in your config.
Here's the view from R2:
172.16.0.0/16 is variably subnetted, 7 subnets, 3 masks
C 172.16.4.0/24 is directly connected, Serial0/0
I 172.16.5.0/24 [100/8976] via 172.16.4.2, 00:00:33, Serial0/0
O 172.16.1.1/32 [110/65] via 172.16.2.1, 00:02:57, Serial0/3
O 172.16.2.0/24 is a summary, 00:03:22, Null0
C 172.16.2.0/28 is directly connected, Serial0/3
O 172.16.3.0/24 is a summary, 00:03:22, Null0
C 172.16.3.0/28 is directly connected, Loopback0
R1-2#sh ip ospf summ
OSPF Process 2, Summary-address
172.16.1.0/255.255.255.0 Metric 16777215, Type 0, Tag 0
172.16.2.0/255.255.255.0 Metric 20, Type 2, Tag 0
172.16.3.0/255.255.255.0 Metric 20, Type 2, Tag 0
...
As you can see, the loopback route from R1 didn't make it.
But you've led me on to something. I'm wary of doing mutual
redistribution without some form of filtering:
router ospf 2
redistribute igrp 10 subnets route-map IGRP2OSPF
!
access-list 1 permit 172.16.4.0 0.0.0.255
access-list 1 permit 172.16.5.0 0.0.0.255
route-map IGRP2OSPF permit 10
match ip address 1
!
172.16.0.0/16 is variably subnetted, 5 subnets, 2 masks
C 172.16.4.0/24 is directly connected, Serial0/0
I 172.16.5.0/24 [100/8976] via 172.16.4.2, 00:00:04, Serial0/0
O 172.16.1.0/28 [110/65] via 172.16.2.1, 00:11:36, Serial0/3
C 172.16.2.0/28 is directly connected, Serial0/3
C 172.16.3.0/28 is directly connected, Loopback0
R1-2#
R1-2#sh ip ospf summ
OSPF Process 2, Summary-address
172.16.1.0/255.255.255.0 Metric 16777215, Type 0, Tag 0
172.16.2.0/255.255.255.0 Metric 16777215, Type 0, Tag 0
172.16.3.0/255.255.255.0 Metric 16777215, Type 0, Tag 0
R1-2#
...
So! It must have something to do with my filtering. But what I don't
understand is, the routes I'm filtering originate in OSPF... Perhaps it
has something to do with the classful summary presented to IGRP for
those routes?
I'm going to do some further testing...
Best regards,
Mas Kato
-----Original Message-----
From: Manuel Ratnakumar [mailto:manuelr@cisco.com]
Sent: Thursday, May 10, 2001 6:57 PM
To: KATO,MAS (HP-USA,ex3)
Cc: Attachment
Subject: B382815
Hi Mas,
Guess what? The command summary address also works for out ospf. The
behaviour changes when you put the default metric while redistributing
ospf
into igrp. Please refer to the configuration that i have attached for
more
details.
Please disregard my previous email explanation about the working of
summary
address command out ospf.
Email me if you want to discsus further on this.
Thanks and Best Regards
Manuel Ratnakumar
-----Original Message-----
From: KATO,MAS (HP-USA,ex3)
Sent: Friday, 11 May 2001 6:02 AM
To: Manuel Ratnakumar
Subject: RE: B382815
Manuel,
So the summary route to null0 -did- install into the routing table?
Interesting... I've never even seen that. What did 'show ip ospf
summary'
indicate for the summary metrics? Also, just out of curiosity, what
default
metric did you use when redistributing into IGRP?
Thanks,
Mas Kato
-----Original Message-----
From: Manuel Ratnakumar [mailto:manuelr@cisco.com]
Sent: Wednesday, May 09, 2001 11:06 PM
To: KATO,MAS (HP-USA,ex3)
Cc: Attachment
Subject: B382815
Mas,
I have tested the ospf summary command.
I have used 11.2.26 and when you summarise the ospf routes into /24 it
does
install the route as ospf summary pointing to the null interface but
when
the redistribution happens the igrp process treats those routes as
inaccessible and with metric 4294967295. See below for the debug igrp
transaction.
02:25:17: IGRP: received update from 172.16.4.2 on Serial1
02:25:17: subnet 172.16.5.0, metric 8976 (neighbor 501)
02:25:33: IGRP: sending update to 255.255.255.255 via Loopback0
(172.16.3.1)
02:25:33: subnet 172.16.2.0, metric=8476
02:25:33: IGRP: sending update to 255.255.255.255 via Serial1
(172.16.4.1)
02:25:33: subnet 172.16.1.0, metric=4294967295
02:25:33: subnet 172.16.2.0, metric=4294967295
02:25:33: subnet 172.16.3.0, metric=4294967295
So the R3 router will not know any routes from the ospf side (/28).
I have also tried the right way which is, installing a static route for
those summary networks and redistributing static on igrp. It works fine.
01:35:29: IGRP: sending update to 255.255.255.255 via Loopback0
(172.16.3.1)
01:35:29: subnet 172.16.2.0, metric=8476
01:35:29: IGRP: sending update to 255.255.255.255 via Serial1
(172.16.4.1)
01:35:29: subnet 172.16.1.0, metric=1
01:35:29: subnet 172.16.2.0, metric=4294967295
01:35:29: subnet 172.16.3.0, metric=4294967295
01:35:35: IGRP: received update from 172.16.4.2 on Serial1
01:35:35: subnet 172.16.5.0, metric 8976 (neighbor 501)
***** See network 172.16.1.0 ************
I hope this results will clear all the doubts you had with summary
address
command.
Is there anything else you want me to do. Feel free to call me or email
me
for any further assistance..
Thanks and Regards
Manuel Ratnakumar
-----Original Message-----
From: KATO,MAS (HP-USA,ex3)
Sent: Tuesday, 8 May 2001 4:20 PM
To: Manuel Ratnakumar
Subject: RE: Case B382815 - *NSA*ETAC: Redistributing OSPF into Classful
Routing Protocols
Manuel,
Yes, please. In fact, why not just test the oldest IOS still in GD.
Here's a simple scenario:
Major net is 172.16.0.0
(R1)--OSPF/28--(R2)--IGRP/24--(R3)
IGRP is passive on the R2's OSPF interface.
A lot of people swear up and down that configuring a /24
'summary-address'
for the /28 network under the OSPF process on R2 will install a null0
route
for the summary that will subsequently propagate to R3.
When I try it with 12.0 and 12.1, 'show ip ospf summary' on R2 shows the
summary with a very high metric and the null0 route is -not- installed,
so
the route, of course, never makes it to R3.
Thanks very much, I really appreciate it.
Regards,
Mas Kato
-----Original Message-----
From: Manuel Ratnakumar [mailto:manuelr@cisco.com]
Sent: Saturday, May 05, 2001 5:40 PM
To: KATO,MAS (HP-USA,ex3)
Subject: RE: Case B382815 - *NSA*ETAC: Redistributing OSPF into Classful
Routing Protocols
Mas,
Yes 11.2 is still in GD. Do you want me to test it for you ?
Thanks and have a Great Week
Manuel
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