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OSPF router getting wrong routes

KenThomassen
Beginner
Beginner

Hey everybody,

I'm working on a project with IPv6 and am currently trying out some stuff with OSPF.

But when i configure a network zith 3 routers, 1 routers always gets wrong routes (Router3).

What might be causing this or how can i fix/prevent this?

I have ipv6 enabled on all the interfaced and the routers have ipv6 unicast-routing.

test2-ospf.PNG

Router3 ospf route:

O   FC00::/64 [110/2]

     via FE80::209:7CFF:FE9B:E802, FastEthernet1/1

O   FC00:0:0:1::/64 [110/2]

     via FE80::20C:85FF:FE48:DA01, FastEthernet1/1

O   FC00:0:0:4::/64 [110/2]

     via FE80::20C:85FF:FE48:DA01, FastEthernet1/1

 

So whenever a packet has to go over Router3 - FA1/0 it fails because there is no route

and there is no dubbel route for when it has to go to network FC00:0:0:1::/64

Router1 ospf route:

O   FC00:0:0:2::/64 [110/2]

     via FE80::20C:85FF:FE48:DA02, FastEthernet1/0

     via FE80::202:16FF:FE30:8301, FastEthernet1/1

O   FC00:0:0:4::/64 [110/2]

     via FE80::20C:85FF:FE48:DA02, FastEthernet1/0

O   FC00:0:0:5::/64 [110/2]

     via FE80::202:16FF:FE30:8301, FastEthernet1/1

Router2 ospf route:

O   FC00::/64 [110/2]
     via FE80::209:7CFF:FE9B:E801, FastEthernet1/1
O   FC00:0:0:3::/64 [110/2]
     via FE80::209:7CFF:FE9B:E801, FastEthernet1/1
     via FE80::202:16FF:FE30:8302, FastEthernet1/0
O   FC00:0:0:5::/64 [110/2]
     via FE80::202:16FF:FE30:8302, FastEthernet1/0

Thanks in advance!

Best regards,

Thomassen Ken

6 Replies 6

Abzal
Rising star
Rising star

Hi,

You may need to check OSPF configuration of interfaces between R1/R3. Because R3 is not establishing neighbor relationship with R1 as result does not see routes that R1 is advertising.

R1:

sh ipv6 protocols

sh ipv6 ospf ne

sh ipv6 ospf int

Hope it will help.

Best regards,
Abzal

Best regards,
Abzal

Hey Abzal,

Thank you for the fast responce.

I have looked into the items you stated in your post.

Everything looks fine to me, but the problem is still there.

i have included a text file with the output of the

show ipv6 protocols

show ipv6 ospf neighbor

show ipv6 ospf interface

maybe i overlooked something?

Best regards,

Ken Thomassen

Hi Ken,

I've looked output you provided and config look OK. But I need some extra info:

R3:

sh run | sec router ospf

The problem might be configured maximum-paths command under OSPFv3 configuration. As you might know OSPF does only equal load balancing. Everything else looks correct for me.

http://www.cisco.com/en/US/tech/tk827/tk831/technologies_tech_note09186a0080094806.shtml

Note. I've checked on GNS3 lab worked prefectly. I didn't tried it on Packet Tracer.

Hope it will help.

Best regards,
Abzal

Best regards,
Abzal

Hi Ken,

The only thing that I find abnormal is the following:

Router3 ospf route:

O   FC00::/64 [110/2]

     via FE80::209:7CFF:FE9B:E802, FastEthernet1/1

The link-local adddress is from R1 and the interface is to R2. This points to either a bug or misconfiguration. What IOS version are you running on R3? Could you please provide the full configuration for R1, R2 and R3?

Regards

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

KenThomassen
Beginner
Beginner

Hi,

I am using Packet Tracer 5.3.3

@Abzal: I have tried the maximum paths for ospf, but the packet tracer routers do not recognise these commands. Packet Tracer also does not recognise the pipe command "sh run | sec router ospf"

@Harold: I have included the running-config off the routers with the version they are running (the same on all).

Best regards,

Ken

Ken,

The configs look good. The only issue I can see at this point is a problem with the IOS version running in this lab. 12.4(15)T1 is quite old. It would definitely be worth upgrading to a more recent version.

Regards

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
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