Hello there, this is your host Habib's a career and this is our chapter six on BGP. And in this lab or in this chapter, we will be going through the steps to configure ebgp using a loopback I decided to put this topology because it's one of the famous topologies when it comes to ebgp. The first point that I wanted to provide here is to show you that how loopback configuration, or loopback hearing is done between two routers that are in different autonomous systems. And the other thing is, each router has dual links to the other router and and the peering is done through the loopback to avoid any disruption, disruptions on the physical connectivity of the routers. So, so that's the benefit of the loopback using the loopback interfaces. Now, when it comes to ebgp, the routers have to be directly connected as you know.

And the other point that needs to be emphasized is that when you use a loopback address for peering, there would be two, two more commands that need to be added into the ebgp configuration. And one is update source loopback. And whatever the loopback is for r three, which is zero, or r two, which is zero, and the other command is going to be ebgp. Multi hop. Number two here can be any number, but two is usually given as as time to learn Live message which is basically in BGP is always one as a default, but to is just to increase the number of hops for ebgp multi hop. So, in our step by step configuration all these commands will be will be included.

The other point I wanted to emphasize is to provide. So, if you do the peering using the loopback there has to be a way for the traffic to communicate between the two routers in that case usually, when it comes to ebgp static routes is usually preferred for for this kind of setup, so, we will add that in our lab as well. Just to show that there is connectivity of, of the loot packs from one round To another if you don't add the static routes obviously the neighboring will be formed between the two routers we will see that but the neighboring is always going to be in an idle form because there will be no traffic going back and forth between the routers. So, so, these are the steps to remember here number one is to complete in the topology will assign a static IP address to all the interfaces we will run ebgp on the routers using the loopback addresses will we will provide static routes for redundancy for redundant links.

So, what we will test is basically if serial one slash one interfaces down the neighboring between the two routers, we're still going to to be there it will not to basically lose It's a neighbor neighbor relationship. Okay, so this sounds like a lot of fun and I hope you can join me in my next session, which is basically configuring and going through this lab step by step. Thank you very much.