Migrating from EIGRP to OSPF

Unanswered Question
Nov 19th, 2008


Can anybody assist me how to migrate from EIGRP to OSPF while in production environment in order to avoid any outage.

Best Regards,

Rahim Amir Ali

I have this problem too.
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csco10716389 Wed, 11/19/2008 - 23:51

After redistribution please use *****clear ip route **** subnet in which want to reset the connection.

waridtel.com Thu, 11/20/2008 - 02:09


I mean to say is there any detailed document which can guide me in migrating from eigrp to ospf.



Giuseppe Larosa Thu, 11/20/2008 - 02:35

Hello Rahim,

here are possible two approaches:

a) deploy OSPF in parallel with EIGRP in all routers in the domain. For the higher AD of OSPF in comparison to EIGRP's AD no changes in the routers routing tables and no issues/impacts.

OSPF database will be populated in all routers.

Using the command sh ip ospf database you can compare the OSPF topology to the EIGRP topology.

(sh ip eigrp topology)

If OSPF DB information is complete the last step to be done in a maintanaince window is:

change the AD of all EIGRP routes (including summary routes to values greater then 110)on all routers.

Verify IP connectivity.

If everything is fine your migration is ended successfully.

b) you could use an approach with ASBR routers:

you divide your EIGRP domain in sub-domains and start to introduce OSPF in the core.

Routers connecting each sub-domain to core will implement EIGRP to OSPF redistribution and can inject a default route to the internal routers or can redistribute also from OSPF to their EIGRP process (in a controlled filtered way)

Later, you migrate each EIGRP sub-domain to OSPF in the same way as described in point A.

We used approach A some years ago to migrate a mobile phone provider IP network with good results.

Hope to help


waridtel.com Thu, 11/20/2008 - 02:42


Thanks Giuseppe. Any document that you would suggest that explains the migration in more detail from the configuration point of view as well.

Best Regards,


waridtel.com Thu, 11/20/2008 - 03:55

Thanks for the help Giuseppe. I would like to have a detailed document if someone else can help me out on this.

Your help is required in this regard.



rgodden Tue, 11/25/2008 - 02:26

The answer has been provided by previous posters. If you dont understand the issues and procedures then you are incapable of carrying out this project.

waridtel.com Tue, 11/25/2008 - 02:36

Well, I do not need to answer you on the forum since you will not like my answer. Anyways I would recommend you to stop using this forum since this forum is for learning and not commenting on anyone's capabilities.


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