Five OSPF network types

There are five OSPF network types:

• Broadcast

• Nonbroadcast

• Point-to-point

• Point-to-multipoint broadcast

• Point-to-multipoint nonbroadcast

Operational characteristics of OSPF network types

Network type	Allow multicast packets?	Configure OSPF to send unicast updates?	DR and BDR elections performed?
Broadcast	Yes	Manual configuration of neighbor routers with the neighbor command is not required	Yes. Default Hello timer is 10 seconds and dead timer is 40 seconds. Issue the ip ospf network broadcast command to configure an OSPF broadcast network.
Nonbroadcast	No	Configure neighbor routers with the neighbor command	Yes. Default Hello timer is 30 seconds and dead timer is 120 seconds. Issue the ip ospf network non-broadcast command to configure an OSPF nonbroadcast network (NBMA) network.
Point-to-point	Yes	Manual configuration of neighbor routers with the neighbor command is not required	No. Default Hello timer is 10 seconds and dead timer is 40 seconds. Issue the ip ospf network point-to-point command to configure an OSPF point-to-point network.
Point-to-multipoint broadcast	Yes	Manual configuration of neighbor routers with the neighbor command is not required	No. Default Hello timer is 30 seconds and dead timer is 120 seconds. Issue the ip ospf network point-to-multipoint command to configure an OSPF point-to-multipoint broadcast network.
Point-to-multipoint nonbroadcast	No	Configure neighbor routers with the neighbor command	No. Default Hello timer is 30 seconds and dead timer is 120 seconds. Issue the ip ospf network point-to-multipoint non-broadcast command tо configure an OSPF point-to-multipoint nonbroadcast network.

*The OSPF broadcast network type is enabled by default on FDDI and Ethernet interfaces.

*To configure OSPF routers interconnecting to nonbroadcast networks, use the neighbor command in router configuration mode. Command configuration details: neighbor (OSPF) (cisco.com)

*NBMA: nonbroadcast multiaccess.

*The OSPF point-to-point network type is enabled by default on High-Level Data Link Control (HDLC) and Point-to-Point Protocol (PPP) serial interfaces.