CCNA: OSPF DR/BDR Election & Path Cost

Three routers share a switched segment and R2–R3 also have a direct link. OSPF is running; now control who becomes DR and which path traffic takes.

Tasks

1. Make R1 the DR on the shared segment by giving its Gi0/0 OSPF priority 255.
2. Stop R3 from ever becoming DR/BDR on that segment (priority 0 on its Gi0/0).
3. Make R2 prefer the shared segment to reach PC3's LAN by raising the cost of R2 Gi0/2 to 100.
4. Change the R2–R3 direct link to OSPF network type point-to-point on both ends.
5. Verify: R1 shows R2 and R3 as neighbours on Gi0/0 and is DR, and PC2 can still ping PC3.