OSPF Stuff

Question 1

OSPF Point to Point Networks

Answer 1

Point to Point Networks – DR and BDR not performed.

Multicast addresses are sent.

Hello/Dead = 10/40.

HDLC+PPP is enabled by default on serial interfaces

Question 2

OSPF Broadcast Networks

Answer 2

Broadcast Networks – DR and BDR elections performed.

Multicast updates are sent so the neighbor command is not needed.

Hello/Dead = 10/40.

OSPF Broadcast network type is enabled by default on FDDI and FE and GE interfaces.

Question 3

OSPF Nonbroadcast networks

Answer 3

Nonbroadcast networks – DR and BDR elections are performed.

Nonbroadcast networks do not allow multicast; therefore, neighbor command is required so OSPF sends unicast updates.

Hello/Dead = 30/120.

OSPF nonbroadcast is also called Nonbroadcast Multiaccess (NBMA) network. should use ip ospf network non-broadcast command.

The OSPF nonbroadcast network type is enabled by default on Frame Relay and X.25 interfaces.

Question 4

OSPF point-to-multipoint broadcast network

Answer 4

OSPF point-to-multipoint broadcast networks operate just like OSPF Point-to-point networks except Hell/Dead = 30/120.

Point to Point Networks – DR and BDR not performed.

Multicast addresses are sent.

Hello/Dead = 10/40.

HDLC+PPP is enabled by default on serial interfaces

Question 5

OSPF point-to-multipoint nonbroadcast

Answer 5

OSPF point-to-multipoint nonbroadcast – multicast cannot be sent; therefore you will need the neighbor command so that OSPF sends unicast updates.