RE: OSPF discontinuous area 0 (IpExpert lab 5)

From: Scott Morris (smorris@ipexpert.com)
Date: Sat Sep 29 2007 - 22:51:11 ART


You aren't supposed to have discontiguous areas! The rule in OSPF is that
everyone within an area must have the same database. If you have some
separation of an area (any area, but particularly area 0) then bad things
happen as you are seeing!

How can you connect areas together in OSPF? There are two methods that may
work for you. But the rule is they have to touch unless you're going to
make them completely separate processes in which case you need to
redistribute!

 
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE-M
#153, CISSP, et al.
CCSI/JNCI-M/JNCI-ER
VP - Technical Training - IPexpert, Inc.
IPexpert Sr. Technical Instructor
 
A Cisco Learning Partner - We Accept Learning Credits!
 
smorris@ipexpert.com
 
Telephone: +1.810.326.1444
Fax: +1.810.454.0130
http://www.ipexpert.com
 

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
George Goglidze
Sent: Saturday, September 29, 2007 2:45 PM
To: Cisco certification
Subject: OSPF discontinuous area 0 (IpExpert lab 5)

Hello all,

I'm doing ipexpert-s lab number 5. and they have discontinuous ospf area 0.

the topology is the following:

R2 FR hub.
R6, R4 FR spokes.

R2 F0/0 interface is in area 0, and FR interface that connects to R4 and R6
is in area 246.

R6 has area 0 too on other interface, let's say int Multilink 1.

when I have interface Multilink 1 in shutdown.
I do receive routes to other areas that are accessible through R2.
but when it's UP, the routes disappear.

------
here's some config:
------------------------------

R2:

router ospf 1
 router-id 2.2.2.2
 log-adjacency-changes
 area 0 authentication message-digest
 area 25 virtual-link 5.5.5.5
 network 2.2.2.0 0.0.0.255 area 0
 network 20.2.2.0 0.0.0.255 area 246
 network 21.2.2.0 0.0.0.255 area 25
 network 150.50.12.0 0.0.0.255 area 0
 network 150.50.25.0 0.0.0.255 area 25
 network 150.50.246.0 0.0.0.255 area 246

interface Serial2/0.1 multipoint
 ip address 150.50.246.2 255.255.255.0
 no ip split-horizon
 ip ospf network broadcast
 ip ospf priority 10
 frame-relay map ip 150.50.246.2 204
 frame-relay map ip 150.50.246.4 204 broadcast frame-relay map ip
150.50.246.6 206 broadcast

------------

R6 config
----------------------

router ospf 1
 router-id 6.6.6.6
 log-adjacency-changes
 area 0 authentication message-digest
 network 6.6.6.0 0.0.0.255 area 246
 network 61.6.6.0 0.0.0.255 area 0
 network 150.50.69.0 0.0.0.255 area 0
 network 150.50.246.0 0.0.0.255 area 246

interface Serial2/0
 ip address 150.50.246.6 255.255.255.0
 encapsulation frame-relay
 ip ospf network broadcast
 ip ospf priority 0
 serial restart-delay 0
 no dce-terminal-timing-enable
 no arp frame-relay
 frame-relay map ip 150.50.246.2 602 broadcast frame-relay map ip
150.50.246.4 602 broadcast frame-relay map ip 150.50.246.6 602 no
frame-relay inverse-arp

interface Multilink1
 ip address 150.50.69.6 255.255.255.0
 ip ospf message-digest-key 1 md5 7 0502160A395C4B1B0D shutdown ppp
multilink ppp multilink group 1

As I know I should be ok with discontinuous area 0. but why does it not
work???

here's the routing table when Multilink 1 is in shutdown.

R6#sh ip route
Codes: C - connected, S - static, 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
       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

     1.0.0.0/32 is subnetted, 1 subnets
O IA 1.1.1.1 [110/66] via 150.50.246.2, 00:01:00, Serial2/0
     2.0.0.0/32 is subnetted, 1 subnets
O IA 2.2.2.2 [110/65] via 150.50.246.2, 00:01:00, Serial2/0
     4.0.0.0/32 is subnetted, 1 subnets
O 4.4.4.4 [110/65] via 150.50.246.4, 00:20:59, Serial2/0
     21.0.0.0/32 is subnetted, 1 subnets
O IA 21.2.2.2 [110/65] via 150.50.246.2, 00:01:00, Serial2/0
     20.0.0.0/32 is subnetted, 1 subnets
O 20.2.2.2 [110/65] via 150.50.246.2, 00:20:59, Serial2/0
     5.0.0.0/32 is subnetted, 1 subnets
O IA 5.5.5.5 [110/129] via 150.50.246.2, 00:01:00, Serial2/0
     6.0.0.0/24 is subnetted, 1 subnets
C 6.6.6.0 is directly connected, Loopback0
     172.4.0.0/24 is subnetted, 4 subnets
O 172.4.0.0 [110/65] via 150.50.246.4, 00:21:00, Serial2/0
O 172.4.1.0 [110/65] via 150.50.246.4, 00:21:00, Serial2/0
O 172.4.2.0 [110/65] via 150.50.246.4, 00:21:00, Serial2/0
O 172.4.3.0 [110/65] via 150.50.246.4, 00:21:00, Serial2/0
     10.0.0.0/32 is subnetted, 1 subnets
O IA 10.1.1.1 [110/66] via 150.50.246.2, 00:01:01, Serial2/0
     61.0.0.0/24 is subnetted, 1 subnets
C 61.6.6.0 is directly connected, Loopback1
     150.50.0.0/16 is variably subnetted, 5 subnets, 2 masks
C 150.50.246.0/24 is directly connected, Serial2/0
C 150.50.7.0/25 is directly connected, FastEthernet0/0
O IA 150.50.1.0/24 [110/66] via 150.50.246.2, 00:01:01, Serial2/0
O IA 150.50.12.0/24 [110/65] via 150.50.246.2, 00:01:01, Serial2/0
O IA 150.50.25.0/24 [110/128] via 150.50.246.2, 00:01:01, Serial2/0

and here's the sh ip route when it's up:

R6#sh ip route
Codes: C - connected, S - static, 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
       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

     4.0.0.0/32 is subnetted, 1 subnets
O 4.4.4.4 [110/65] via 150.50.246.4, 00:21:25, Serial2/0
     20.0.0.0/32 is subnetted, 1 subnets
O 20.2.2.2 [110/65] via 150.50.246.2, 00:21:25, Serial2/0
     6.0.0.0/24 is subnetted, 1 subnets
C 6.6.6.0 is directly connected, Loopback0
     172.4.0.0/24 is subnetted, 4 subnets
O 172.4.0.0 [110/65] via 150.50.246.4, 00:21:25, Serial2/0
O 172.4.1.0 [110/65] via 150.50.246.4, 00:21:25, Serial2/0
O 172.4.2.0 [110/65] via 150.50.246.4, 00:21:25, Serial2/0
O 172.4.3.0 [110/65] via 150.50.246.4, 00:21:25, Serial2/0
     61.0.0.0/24 is subnetted, 1 subnets
C 61.6.6.0 is directly connected, Loopback1
     150.50.0.0/16 is variably subnetted, 4 subnets, 3 masks
C 150.50.246.0/24 is directly connected, Serial2/0
C 150.50.7.0/25 is directly connected, FastEthernet0/0
C 150.50.69.0/24 is directly connected, Multilink1
C 150.50.69.9/32 is directly connected, Multilink1

all the IA routes dissapeared.

Many thanks for any help,



This archive was generated by hypermail 2.1.4 : Sat Oct 06 2007 - 12:01:17 ART