Hi Rene
Very good article. Can you put up an explanation on how to design route based failover between two DC’s using BGP AS-Prepend and iBGP/OSPF between DC’s
Hi Vishal,
Glad to hear you like it. AS prepending is only used for EBGP, when you use IBGP the AS number is the same. We can use some of the other BGP attributes to influence IBGP. If there’s any particular design you are looking for, send me a mail…I might be able to create a nice tutorial but I’ll need some more information 
Rene
Hi Rene,
it’s a very nice explanation.
Also can you describe the process of How do routers form OSPF adjacencies when they first boot-up?
Thank you
BR
Taslim
Hi Taslim,
Thanks. I think this will help:
Rene
Hi Rene,
Please point me to the link in your site which explains about AS Prepending. Not able to locate it. thanks
The 4 videos listed in this specific page have the same content. Not sure, whether that was deliberate or an oversight. Nice explanation of OSPF. thanks.
Hmm that’s strange, I’m seeing 4 different videos here.
Nice job on the ospf articles! I went through most of them and configured ospf on my home network. As I got through your lessons I felt I now understand this. Although configuring a real network there are always differences. First after a “show ospf database” the network ID of my router was not the same as the interface… After removing and reconfiguring ospf several times I finally remembered that the ID was that of the highest IP address on the device, not the address of the interface I was configuring. I also configured md5 authentication between my two devices. These articles are great, but I found you never really learn it until you actually do it.
Thanks for the great information!
Also, my configuration was between an ASA security appliance and a router, in which there were a few differences in the commands on the ASA. So I had to do a little research on this. It was a little different, but everything worked as you described.
Thanks again!
Hi Chris,
Glad to hear you like them When you learn any networking it really helps to read some of the theory first and then try to configure something yourself. The theory is needed to understand what the commands are for but practice is where everything really “sinks in”.
It’s a good idea to practice everything you read here yourself…you also might like my labs on gns3vault.com for this.
Rene
The configuration of the ASA and Cisco IOS is pretty similar, if you understand OSPF then you can implement it on pretty much any device. The main difference is the commands that you’ll have to use.
Rene,
Hello, one more question on this I thought of. What if two routers had the same loopback addresses?
Hi Chris,
That will cause some issues if two OSPF routers end up with the same router ID. Make sure you use unique IP addresses throughout your network
Rene
Hi Rene,
Thank you for the awesome explanation.
I would really appreciate if you can include some best practices among the vast amount of things we can do here.
I really liked the way you put in the usage of loopback interfaces, probably these are trivial settings but they make real sense for beginners.
Regards,
Amar
Hi Amar,
You are welcome, glad to hear you like it! I do my best to include best practices in my examples. If you have any questions about certain topics, just let me know and I can always elaborate on it.
Rene
Rene,
Excellent explanation!!! Thanks you so much for these videos and great article.
Hug
Hi Rene ,
In BGP and LDP protocol TCP is used as transport protocol and also for sending keepalive messages.
Why the same TCP is not followed in OSPF neighbor establishments or exchanging routes ? Could you please elaborate it ?
Thanks
Anand
Hi Anand,
One of the major differences between BGP and any of the IGPs (RIP, OSPF, EIGRP, IS-IS) is that BGP always uses unicast. OSPF for example uses multicast on multi-access networks and has autodiscovery of neighbors.
Rene