Which OSPF network type uses DR and BDR elections?

Which OSPF network type uses DR and BDR elections?

• A. Broadcast
• B. Point-To-Point
• C. Nonbroadcast
• D. Point-To-Multipoint

Answer: (A)

In OSPF, DR and BDR elections happen on networks where many routers share the same multi-access segment. The goal is to limit how many adjacencies and LSAs must be flooded, by designating a single router (the Designated Router) to coordinate flooding and a Backup Designated Router to take over if the DR fails. Broadcast networks are the classic example of this setup. On Ethernet-like shared segments, multiple routers connect to the same network, so electing a DR helps organize adjacencies efficiently; all other routers form adjacencies with the DR, and the BDR serves as a backup. That’s why this network type is associated with DR/BDR elections. In contrast, point-to-point links connect only two routers, so there’s no need for a DR or BDR. Point-to-multipoint and non-broadcast configurations behave differently and typically don’t rely on DR/BDR in the same way.

In OSPF, DR and BDR elections happen on networks where many routers share the same multi-access segment. The goal is to limit how many adjacencies and LSAs must be flooded, by designating a single router (the Designated Router) to coordinate flooding and a Backup Designated Router to take over if the DR fails.

Broadcast networks are the classic example of this setup. On Ethernet-like shared segments, multiple routers connect to the same network, so electing a DR helps organize adjacencies efficiently; all other routers form adjacencies with the DR, and the BDR serves as a backup. That’s why this network type is associated with DR/BDR elections.

In contrast, point-to-point links connect only two routers, so there’s no need for a DR or BDR. Point-to-multipoint and non-broadcast configurations behave differently and typically don’t rely on DR/BDR in the same way.