A friend of mine asked me about the OSPF forwarding address. The question was why must the network type be broadcast for the FA to be set? Why is not point to point and point to multipoint network type valid?
Tiebreakers with routes from different OSPF processes
This post is inspired by a discussion at Twitter with Ivan Pepelnjak and Nicolas Michel. Nicolas asked what happens when there is the same route from two different OSPF processes. Which one will be selected? Ivan explained how to use
ASBR in NSSA – Choosing what IP to use as forwarding address
OSPF is one of the protocols where the details are very important. It has lots of bits and pieces to make it run in a proper way. I have described the forwarding address in an earlier post and this time
Route redistribution – Route-maps and tagging
Earlier I have done some posts on route redistribution and on route filtering in different protocols. I wanted to expand on this by showing different ways we can tag and do filtering with route-maps when doing route redistribution. We start
OSPF – Use of forwarding address
In OSPF and other routing protocols we have something called forwarding address. This can be used to route traffic in another direction than to the router that originated the LSA. We start with the following topology. It’s a basic OSPF
Some interesting facts of OSPF
OK so clearly I haven’t been updating a lot lately due to my very busy situation. I’m sorry for that but my former colleague Henri keeps nagging me for an update so I decided to write on some interesting tidbits
OSPF: Anatomy of a routing protocol
To become a CCIE you need detailed knowledge of OSPF. Most candidates will have read the TCP/IP Volumes by Doyle and maybe even the RFC written by J Moy. This book is also written by J Moy and it is
OSPF magic – Make interarea routes become intraarea
This is a follow up post to my last OSPF post about repairing area 0. In the comments section Ray asked me what we can do if we have a scenario where we have another area that is discontigous. In
Repairing a discontigous area 0 in OSPF
First start by looking at the diagram above. This is a scenario I ran into while doing my mock lab. It is pretty obvious that we will have issues with OSPF since area 0 is discontigous. You should be able
How well do you really know OSPF?
OSPF is by far the most complicated IGP on the RS lab if we go in to the details of the protocol and the loop prevention mechanisms. While doing some labs this week I ran in to some interesting issues.