In an OSPF routing domain, how many routers must be specified as DR and BDR in a broadcast network?

In an OSPF (Open Shortest Path First) routing domain that operates on a broadcast network, one router is designated as the Designated Router (DR) while another is chosen as the Backup Designated Router (BDR). This configuration is essential to minimize the amount of OSPF traffic on the network.

The DR is responsible for generating and flooding link-state advertisements to other routers in the broadcast segment. The BDR provides redundancy and takes over the responsibilities of the DR if it fails. Thus, at least two routers are required: one for the DR and one for the BDR.

Having a DR and BDR is crucial as it helps manage routing updates efficiently. It prevents every router in the network from having to send routing information to every other router, which would lead to excessive traffic and inefficiency.

In a broadcast network, it is not necessary to have more than two designated routers because the DR and BDR can efficiently handle the routing tasks among the other non-designated routers, who only need to send their updates to these two routers. This structure is specifically designed to optimize network performance in a broadcast environment.

Consequently, the requirement of having at least two routers specified as DR and BDR ensures that the OSPF protocol