I am still in the same LAB scenario. From the last LAB we know that R1 (who has router id 126.96.36.199) is the DR and R3 (who has the router id 188.8.131.52) is the BDR.
Now I want to make the change needed to make R2 as the DR but I am not allowed to change the router id on R2.
Remember that at this moment, the priority on all 3 routers has a value of 1, that’s why the routers will check who has the highest router id to make it the DR. However, if one router has a higher priority than all other routers, then he will end up to be the DR.
For this, I need to change the priority on R2 and make 10. Then 10 is higher than 1 (which is on R1 and R3), then R2 should become the DR.
Let’s 1st check what is the priority on R2.
R2 (as R1 and R3) has a priority of 1. For now R2 is in DROther state. Let’s change the priority on R2 to 10 and check if it will become the DR.
I have changed the priority to 10 on R2. However, if we check we will see that R2 is still a DROther and that’s because OSPF doesn’t change the DR/BDR right away in order to keep the stability and convergence on the routing. For this you need to reset the OSPF process on the 3 routers. Before I do that, let me show you that R2 is still DROther while he has the new priority.
You see that R2 is still in DROther state but has priority on 10. Let’s clear the OSPF process on the 3 routers together.
The OSPF process has been reset on the 3 routers and they have formed OSPF neighborship. Let’s check if R2 is now the DR.
Here we go!!!! R2 is now the DR because he has the higher priority. R1 should be the BDR because his router id is higher than the router id of R3 (184.108.40.206 is higher than 220.127.116.11), and that’s what is says on the above output.
Let’s check if R3 has DROther state.
Correct!!! R3 has now the DROther state. That’s what I wanted to show you in this LAB. Please leave the LAB operational because we need to use it in the upcoming one.