Instead of going with that model, OSPF elects one of the routers on the shared segment the Designated Router (DR), and another the Backup Designated Router (BDR).Whenever a change occurs, an OSPF router will send an update to the multicast address 188.8.131.52, which sends the update to the DR and BDR.Besides the blog, we have our security auditing tool Lynis.
Since R1 is neither the DR or BDR, it is a member of the multicast group “OSPFAll Routers”.
Once neighbor relationships have been established, routing information must be distributed via Link State Advertisements, or LSAs.
In a shared-media environment, this can be problematic.
The DR will, in turn distribute the update to the non-DR routers.
The BDR is just a backup, it acts as a non-DR router unless the DR goes offline.