Bad OSPF summary routing due to poor IP addressing

The below is a real life example. Due to the poor IP addressing, you will see wrong OSPF summary routing has been added in the routing table under specific condition.ospf

As RFC 2328 suggests,the metric for summary routes in which the component of the summary route with the maximum / largest metric would determine the metric of the summary.

On Router 1, you will see the two routing entries for 10.16.192.0/23 have been added into routing table.

routing table

FYI:Route summary metric in RFC 1583

Area border routers then summarize the area contents (for distribution to the backbone) by advertising a single route for each address range.  The cost of the route is the minimum cost to any of the networks falling in the specified range.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s