From: Ben-Shalom, Omer (omer.ben-shalom@xxxxxxxxx)
Date: Sun Nov 11 2001 - 09:17:12 GMT-3
Other people may correct me but on the surface of it you are getting a
summary route to the classful network 200.0.0.0 , do no auto summary and
check again.
Omer.
-----Original Message-----
From: Albert Lu [mailto:albert_ccie@yahoo.com]
Sent: Sun, November 11, 2001 1:13 PM
To: 'Ccielab (E-mail)'
Subject: Weird IGRP and EIGRP Redistribution Findings!!
Hi All,
Ok, I've found something really strange redistributing between EIGRP and
IGRP. From what I know, the FLSM and VLSM redistribution will only
redistribute routes in the VLSM domain that has the same subnet length as
the interface of the router connecting the two networks together. For
instance, if a router that connects IGRP and EIGRP together and they both
have /24 subnet length, then only the /24 networks in EIGRP (the VLSM) will
be redistributed into IGRP.
I've encounterd a scenario with two routers, where the border router between
EIGRP and IGRP has a loopback interface of /32 belonging to EIGRP. The
interfaces in EIGRP and IGRP of the border router is /24, so I would assume
that any other network that is not a /24 in EIGRP will not be redistributed
into IGRP.
However, this /32 network is being redistributed into IGRP from EIGRP as a
/24. So does that mean the redistribution of only /24 networks only apply to
networks that are not directly connected to the border router?
Does this also apply for OSPF and IGRP(or RIP) redistribution?
Take a look at my configs, debugs and routing tables. Basically, it's two
routers with RA being the border router that has IGRP and EIGRP running on
it. RB has only IGRP running on it.
The 200.0.0.2/32 loopback interface belongs to the EIGRP process, however
after the redistribution in IGRP process on the same router, it is sent out
to RB as 200.0.0.0/24.
Please comment and help!! =)
Thanks
Albert
RA
------
hostname RA
!
ip subnet-zero
!
interface Loopback0
ip address 10.2.17.1 255.255.255.0
no ip directed-broadcast
!
interface Loopback10
ip address 200.0.0.2 255.255.255.255 <-------***** This has a mask of /32
no ip directed-broadcast
!
interface Serial0
ip address 10.1.1.1 255.255.255.0
no ip directed-broadcast
clockrate 64000
!
interface Serial1
ip address 10.2.2.1 255.255.255.0
no ip directed-broadcast
clockrate 64000
!
router eigrp 50
passive-interface Loopback10
network 200.0.0.0 <-----------******* Network
200.0.0.2/32 part of EIGRP, not IGRP
!
router igrp 100
redistribute eigrp 50 metric 1000 100 255 1 1500
passive-interface Loopback0
passive-interface Serial0
network 10.0.0.0
!
no ip classless
!
RC
-------
hostname RC
!
ip subnet-zero
!
interface Loopback0
ip address 10.2.25.2 255.255.255.0
!
interface Serial0
ip address 10.2.2.2 255.255.255.0
!
router igrp 100
redistribute connected
passive-interface Loopback0
network 10.0.0.0
!
ip classless
!
RA Routing Table
----------------
04:58:51: IGRP: received update from 10.2.2.2 on Serial1
04:58:51: subnet 10.2.25.0, metric 8976 (neighbor 501)
04:59:17: IGRP: sending update to 255.255.255.255 via Serial1 (10.2.2.1)
04:59:17: subnet 10.1.1.0, metric=8476
04:59:17: subnet 10.2.17.0, metric=501
04:59:17: network 200.0.0.0, metric=501
RA#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate
default
U - per-user static route, o - ODR
Gateway of last resort is not set
200.0.0.0/32 is subnetted, 1 subnets
C 200.0.0.2 is directly connected, Loopback10
10.0.0.0/24 is subnetted, 4 subnets
C 10.2.2.0 is directly connected, Serial1
C 10.1.1.0 is directly connected, Serial0
I 10.2.25.0 [100/8976] via 10.2.2.2, 00:00:10, Serial1
C 10.2.17.0 is directly connected, Loopback0
RA#
RC Routing Table
----------------
05:01:02: IGRP: sending update to 255.255.255.255 via Serial0 (10.2.2.2)
05:01:02: subnet 10.2.25.0, metric=501
05:01:29: IGRP: received update from 10.2.2.1 on Serial0
05:01:29: subnet 10.1.1.0, metric 10476 (neighbor 8476)
05:01:29: subnet 10.2.17.0, metric 8976 (neighbor 501)
05:01:29: network 200.0.0.0, metric 8976 (neighbor 501)
<--------------****** EIGRP 50 redistributed into IGRP 100
RC#
RC#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter
area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
I 200.0.0.0/24 [100/8976] via 10.2.2.1, 00:01:19, Serial0
10.0.0.0/24 is subnetted, 4 subnets
I 10.1.1.0 [100/10476] via 10.2.2.1, 00:01:19, Serial0
C 10.2.2.0 is directly connected, Serial0
C 10.2.25.0 is directly connected, Loopback0
I 10.2.17.0 [100/8976] via 10.2.2.1, 00:01:19, Serial0
RC#
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