From: Scott Morris (swm@emanon.com)
Date: Mon Nov 22 2004 - 00:28:41 GMT-3
The effect on your routing table will be the same using either command...
With the interface command though, your router will actually generate
packets giong out a non-existent interface. Go figure. :)
Scott
_____
From: mani poopal [mailto:mani_ccie@yahoo.com]
Sent: Sunday, November 21, 2004 3:06 PM
To: mani poopal; swm@emanon.com; ccielab@groupstudy.com
Subject: RE: default route origination in ISIS
Hi scott,
I configured R1 as L2(area 55) and R2 as L1/L2(area 11) and R3 as L1(area
11). In the routing table of R3 now I am seeing L1 routes from R2 and
default route L1 route. Thanks for your information. Scott, what is the
difference between advertising a loopback in to isis( router isis interface
command) vs passive-interface lo 0 under router mode. Again in the routing
table of R3, I am seeing default routes and other L1 route originated by
R2(same area router). Is there is any way to receive only default route at
R3. R3 configs are included with this email.
thanks
Mani
==================================
Routing table, before making R3 as level-1 router:
R3#show 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, su - IS-IS summary, 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
140.4.0.0/24 is subnetted, 2 subnets
C 140.4.1.0 is directly connected, Loopback1
C 140.4.2.0 is directly connected, Loopback2
20.0.0.0/24 is subnetted, 1 subnets
C 20.1.1.0 is directly connected, Serial1
111.0.0.0/24 is subnetted, 1 subnets
i L1 111.11.1.0 [115/10] via 20.1.1.2, Serial1
160.6.0.0/24 is subnetted, 3 subnets
C 160.6.2.0 is directly connected, Loopback4
C 160.6.3.0 is directly connected, Loopback5
C 160.6.1.0 is directly connected, Loopback3
130.3.0.0/24 is subnetted, 2 subnets
i L2 130.3.1.0 [115/20] via 20.1.1.2, Serial1<---advetised by
"passive-interface lo 2"
i L2 130.3.2.0 [115/30] via 20.1.1.2, Serial1<---advertised by" ip router
isis command"
10.0.0.0/24 is subnetted, 1 subnets
i L1 10.1.1.0 [115/20] via 20.1.1.2, Serial1
150.5.0.0/24 is subnetted, 2 subnets
C 150.5.3.0 is directly connected, Loopback0
i L2 150.5.1.0 [115/20] via 20.1.1.2, Serial1
============================================================================
====
I changed the command at R3-->is-type level-1
R3#show 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, su - IS-IS summary, 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 20.1.1.2 to network 0.0.0.0
140.4.0.0/24 is subnetted, 2 subnets
C 140.4.1.0 is directly connected, Loopback1
C 140.4.2.0 is directly connected, Loopback2
20.0.0.0/24 is subnetted, 1 subnets
C 20.1.1.0 is directly connected, Serial1
111.0.0.0/24 is subnetted, 1 subnets
i L1 111.11.1.0 [115/10] via 20.1.1.2, Serial1<-----Anyway to stop these
160.6.0.0/24 is subnetted, 3 subnets
C 160.6.2.0 is directly connected, Loopback4
C 160.6.3.0 is directly connected, Loopback5
C 160.6.1.0 is directly connected, Loopback3
10.0.0.0/24 is subnetted, 1 subnets
i L1 10.1.1.0 [115/20] via 20.1.1.2, Serial1
150.5.0.0/24 is subnetted, 1 subnets
C 150.5.3.0 is directly connected, Loopback0
i*L1 0.0.0.0/0 [115/10] via 20.1.1.2,
Serial1<-----------------------GENERATED DEFAULT ROUTE
================================================
mani poopal <mani_ccie@yahoo.com> wrote:
Hi Scott,
Thanks for the quick reply.
Mani
Scott Morris wrote:
ISIS does not generate and outbound 0/0 route.
If you have an L1 adjacency, you'll get whatever intra-area routes you are
supposed to get. When your L1/L2 router connects to another L2 neighbor
THEN all of those same L1 routes to the same L1 router will be sent with an
ATT bit set.
This ATT bit indicates that the advertising router is attached to another
outside area. The receiving router will then create their own 0/0 route
towards the L1/L2 router solely based on receipt of aroute with the ATT bit
set.
So if you want to see this in action, you really need to have three routers.
One L2 (area 1) one L1/L2 (area 2) and one L1 (area 2)...
HTH,
Scott Morris, MCSE, CCDP, CCIE4 (R&S/ISP-Dial/Security/Service Provider)
#4713, JNCIP, CCNA-WAN Switching, CCSP, Cable Communications Specialist, IP
Telephony Support Specialist, IP Telephony Design Specialist, CISSP
CCSI #21903
swm@emanon.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of mani
poopal
Sent: Sunday, November 21, 2004 2:00 PM
To: ccielab@groupstudy.com
Subject: default route origination in ISIS
Hi Group,
I tried to configure RIP and ISIS. My HUB router is R2(runs rip and isis
and redistributes) in the R3 spoke router I am seeing all rip routes and
isis L2 routes. I thought if I could make the is-type for R3 to level 1,
hub router R2 should geneate a default route. I configured
(config-router)#is-type level-1 at R3, this configuration stopped learing of
all L2 routes and I could not see a default route originated by my Hub
router(level1/level2 I even changed the is type to level 2 only). I am
posting my config at R2 and R3, any feed back is appreciated.[IN THIS CONFIG
I REMOVED THE IS-TYPE LEVEL-1 IN R3]
thanks
Mani
==========================================
R3(spoke router)
interface Serial1
ip address 20.1.1.3 255.255.255.0
ip router isis
!
router isis
net 11.0000.0000.0003.00
passive-interface Loopback0
passive-interface Loopback1
passive-interface Loopback2
passive-interface Loopback3
passive-interface Loopback4
passive-interface Loopback5
==
R3#show 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, su - IS-IS summary, 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
140.4.0.0/24 is subnetted, 2 subnets
C 140.4.1.0 is directly connected, Loopback1
C 140.4.2.0 is directly connected, Loopback2
20.0.0.0/24 is subnetted, 1 subnets
C 20.1.1.0 is directly connected, Serial1
111.0.0.0/24 is subnetted, 1 subnets
i L1 111.11.1.0 [115/10] via 20.1.1.2, Serial1
160.6.0.0/24 is subnetted, 3 subnets
C 160.6.2.0 is directly connected, Loopback4
C 160.6.3.0 is directly connected, Loopback5
C 160.6.1.0 is directly connected, Loopback3
130.3.0.0/24 is subnetted, 2 subnets
i L2 130.3.1.0 [115/10] via 20.1.1.2, Serial1
i L2 130.3.2.0 [115/10] via 20.1.1.2, Serial1
10.0.0.0/24 is subnetted, 1 subnets
i L2 10.1.1.0 [115/10] via 20.1.1.2, Serial1
150.5.0.0/24 is subnetted, 3 subnets
C 150.5.3.0 is directly connected, Loopback0
i L2 150.5.2.0 [115/10] via 20.1.1.2, Serial1
i L2 150.5.1.0 [115/10] via 20.1.1.2, Serial1
======================================================
R1(HUB ROUTER) RUNNING RIP & ISIS AND MUTUAL REDISTRIBUTION:
interface Serial0
ip address 10.1.1.2 255.255.255.0
clockrate 56000
!
interface Serial1
ip address 20.1.1.2 255.255.255.0
ip router isis
clockrate 56000
!
router isis
net 11.0000.0000.0002.00
redistribute rip
passive-interface Loopback10
!
router rip
version 2
redistribute connected route-map ABC
redistribute isis level-1-2 metric 3
network 10.0.0.0
network 150.5.0.0
no auto-summary
!
ip classless
no ip http server
!
route-map ABC permit 10
match interface Serial1
B.ENG,A+,CCNA,CCNP,CCNP-VOICE, CSS1,CNA,MCSE
(416)431 9929
MANI_CCIE@YAHOO.COM
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