Best practice Route Reflector

[Oliver Seufer]

Hello,

I would like to gather some thoughts on whether I should use a Route Reflector
or not, and if I do need one, what would be the best practice.

Let's begin with the setup. I have four BGP routers located in two different data centers:
* Each router (r1, r2, r3, r4) has an iBGP session established with the other BGP routers.
* Two routers (r1 and r2) receive a full table from transit providers.
* The other two routers (r3 and r4) receive the best routes (full table) from r1 and r2.
* Additionally, r3 and r4 have peering connections with external parties and
  provide a default route via iBGP to other systems.

Schematic representation of the setup

data center 1      data center 2
r1 ------------------ r2
  \                  /
   ------------------
  /                  \
r3                    r4

Under normal conditions, I do not require a Route Reflector in this setup.

However, there are situations where r3 can still reach r1 but not r2 and r4.
Additionally, r1 can still reach r2. In this specific situation, r3 only
receives the best route from r1 and not the learned routes from r2.

I am aware that I can use a Route Reflector to address this issue, but I am not
entirely certain if it is a suitable solution for my setup. Currently, my plan
is to use r1 and r2 as the Route Reflector Cluster (with next hop self), while
r3 and r4 would connect as non-Route Reflector clients to r1 and r2.

So, the requirement is for r3 and r4 to always receive a full table.

Regarding the approach, using a Route Reflector seems like a reasonable
solution in this case. However, there might be alternative and potentially
better solutions available.

Thanks,

Oliver