OSPF-BGP network connection

Hello Shaji

Redistributing OSPF into BGP and vice versa is not always necessary. The need for redistribution depends on your specific network design and routing requirements. For example, you may have a default route that routes all traffic from the OSPF domain to the BGP domain, so your OSPF domain doesn’t need to know all of the routes in the BGP domain. In other cases, you may have multiple connections to multiple BGP domains, and you may need to know in which direction to send traffic with a particualr destination. So the answer to your first question is, it depends on your routing setup and what you want to achieve.

However, when you do redistribute, it’s crucial to understand that it can lead to routing loops if not properly managed. Redistribution should be done carefully, because it can result in suboptimal routing, increased CPU load on routers, and routing loops. Therefore, it’s recommended to use route-maps when redistributing to control exactly what routes are redistributed and to set certain attributes.

Route-maps provide more granular control over the redistribution process. They can filter which routes are redistributed based on various criteria like prefix, metric, etc. and can also set attributes for the redistributed routes.

Remember, the best practice is to have a clear routing policy in place before starting the redistribution process. Always plan your redistribution and apply it with caution.

If you need further help on this, please tell us a little bit more about your specific topology and what you want to achieve.

I hope this has been helpful!