Home » Cisco » 300-410 » Which iBGP routers must be configured as route reflectors to advertise all routes to restore reachability across all networks?
Exhibit:
An engineer configured R2 and R5 as route reflectors and noticed that not all routes are sent to R1 to advertise to the eBGP peers. Which iBGP routers must be configured as route reflectors to advertise all routes to restore reachability across all networks?
A. R1 and R4
B. R1 and R5
C. R4 and R5
D. R2 and R5
Correct Answer: C
Explanation/Reference:
Explanation:
When R2 & R5 are route reflectors (RRs), routes from R4 & R8 are advertised to R5 and R5 advertises to R2. But R2 would drop them as R2 is also a RR. Therefore some routes are missing on R1 to advertise to eBGP peers.
Good reference:
https://www.ciscolive.com/c/dam/r/ciscolive/emea/docs/2015/pdf/TECRST-2310.pdfRoute reflectors (RR) must be fully iBGP meshed so we cannot configure RR on both R1 andR5.
We should choose routers at the center of the topology RRs, in this case R4 & R5.
