OSPF - interconnecting another domain

[tjskier69]

Hi folks again,

I have another question, which is how you interconnect 2 or more OSPF domains or AS's together so that each AS would see the other routes as external. Would BGP be really necessary? Also assume that a private connection between them does is a possibility.

Any ideas.

[pkhatri]

All routes injected into one OSPF domain from another appear as external - you don't have a choice in the matter.

BGP is not necessary. In the context of Cisco IOS, you could run 2 separate OSPF processes and redistribute between them.

Hope that helps - pls rate the post if it does.

Paresh

[arvindchari]

In addition to Paresh's post, Id like to add that you can match only selected types of LSA's to be redistrubuted. Ive found this invaluable in a couple of instances.

Here's a sample configuration:

Router1#configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router1(config)#router eigrp 11

Router1(config-router)#redistribute ospf 55 match external type 1

Router1(config-router)#end

Router1#

HTH

Please rate posts that help

Regards

Arvind

[balajitvk]

Hi skier,

You can very well interconnect two different ospf domains with the redistribution of routes among them.

Here is the site to provide some configuration examples,

http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a0080531fd2.shtml#singlered

Rgs,