Can you clarify what it is that you are requesting? Can you give us a little more information about the architecture you are trying to create and for what purpose?
Also keep in mind that if you have a suggestion for a lesson, you can always go to the Member Ideas page shown below, and make a suggestion for a particular lesson you’d like to see. You may find that others have made similar suggestions and you can add your voice to theirs.
In the meantime, take a look at this Cisco documentation that describes BGP route reflectors and how they can be incorporated into an ACI Fabric in a data center.
As with any BGP AS, all routers within an AS must be reachable in order for BGP to function correctly. Whether you use an RR or not, all routers within AS 123 must have routing established between them. This is typically achieved using an IGP like OSPF or EIGRP. So yes, an IGP should run in the AS to ensure reachability between all routers.
Notice how the next-hop wasn’t changed, it still refers to R1. What has changed was the addition of two new path attributes - Cluster List and Originator ID that Rene covers in his lesson.
The originator_ID is the router ID of the router from who the route originates from. It’s used as a loop prevention mechanism. If the router sees its own RID here, it will discard the packet.
Yes, route reflectors will only reflect routes. Configurations like update-source and next-hop-self are functions that operate within the confines of the router on which they are configured.
My understanding is for RRs, if one Router in a Cluster gets a “no-advertise” community, it will not advertise those routes to other RRs in the cluster.
Are there any techniques to allow for that?
The only thing I can think of is set your own internal community and filter appropriately on inbound / outbound Route Maps.
Yes, you’re right. In a BGP RR cluster, if an RR or even one of its clients receives a route with the “no-advertise” community, it will not advertise this route to any other BGP peer, including an RR, or RR clients within the cluster.
To overcome this, you can indeed use your own internal community and filter accordingly using inbound or outbound Route Maps. This way, you can manipulate the route advertisements as per your requirements.
Here’s a brief example of how you can do this:
Remove the “no-advertise” community from the received routes.
Set your own community.
On the outbound direction, match your community and set the “no-advertise” community back again if needed.
You are the master of your own domain (i.e. your own AS) so you can manipulate the communities as you see fit. Remember to apply these configurations on routers in the cluster to ensure consistency, otherwise, it can lead to routing loops or suboptimal routing.
At this time, we don’t have a lesson with multiple RRs. However, on Rene’s GNS3 Vault site, he does have a lab with two RRs. You can find it here:
You can use this as a base from which you can experiment with multiple RRs. In the meantime, you can also make a suggestion for a new lesson in NetworkLessons with multiple RRs by going to the following Member Ideas page:
There, you can make your own suggestions, and you may find that others have made similar suggestions, and you can add your voice to theirs.
