Exam 350-401 topic 1 question 114 discussion

Provided answer is correct - B Compatible Network types: Broadcast to Broadcast Non-broadcast to Non-broadcast Point-to-Point to Point-to-Point Broadcast to Non-broadcast (adjust hello/dead timers) Point-to-Point to Point-to-Multipoint (adjust hello/head timers)

B is correct

Point-to-point and point-to-multipoint do not use DR/BDR so you can use them with BC and Non-Bc since the BCor Non-BC use the DR/BDR. The correct answer BC with Non-BC

https://learningnetwork.cisco.com/s/question/0D53i00000Kt4FfCAJ/ospf-network-types Some adjustments are necessary however (timers, plus static neighbour configuration on one end)

tested: router ospf 1 passive-interface default no passive-interface Vlan10 network 0.0.0.0 255.255.255.255 area 0 neighbor 192.168.255.3 sw1# sw1# sw1#s runn int vlan 10 Building configuration... Current configuration : 142 bytes ! interface Vlan10 description "MGMT" ip address 192.168.255.2 255.255.255.0 ip ospf network non-broadcast ip ospf hello-interval 10 end sw1#sh ip ospf nei Neighbor ID Pri State Dead Time Address Interface 10.0.0.1 1 FULL/BDR 00:00:31 192.168.255.3 Vlan10 sw1#

Provided answer is correct

The correct answer is B.

B is correct

A is the only option that both side have the same timers

I'll go for A because broadcast network cant form adjacencies with non-broadcast netwoeks

checked it in GNS3, D doesn't work. Neighborship builds but routes don't get exchanged, routing table remains empty. It's because the method of exchanging routes is different hence it isn't compatible. R4#show ip ospf neigh Neighbor ID Pri State Dead Time Address Interface 3.3.3.3 1 FULL/BDR 00:00:35 10.0.1.1 GigabitEthernet0/0 R3#show ip ospf neigh Neighbor ID Pri State Dead Time Address Interface 4.4.4.4 0 FULL/ - 00:00:37 10.0.1.2 GigabitEthernet0/0

from Pearsontestprep's ENARSI test explanation Question24: "Although it is highly recommended that network types match, it is not a requirement as long as the network types are compatible. Since the network types Broadcast and Point-to-Point use the same timers (Hello 10 and Dead 40), by default they will be able to form a neighbor adjacency with each other. Although Broadcast uses a DR/BDR and Point-to-Point does not, that difference will not prevent them from forming a full neighbor adjacency and synchronizing their LSDBs." Means adjust timers and all combis should be compatible imho.

I think it is A.... go to your router and try this... Hub(config)#interface serial 0/0 Hub(config-if)#ip address 192.168.123.1 255.255.255.0 Hub(config-if)#encapsulation frame-relay Hub(config-if)#ip ospf network point-to-multipoint non-broadcast Hub(config-if)#exit Hub(config)#router ospf 1 Hub(config-router)#network 192.168.123.0 0.0.0.255 area 0 Hub(config-router)#neighbor 192.168.123.2 Hub(config-router)#neighbor 192.168.123.3

i think it depends on whether choose DR/BDR instead of hello dead time cause it can be changed so I agree on B

A and D Broadcast Hello: 10 Wait: 40 Dead: 40 Point-to-point Hello: 10 Wait: 40 Dead: 40 Non-broadcast Hello: 30 Wait: 120 Dead: 120 Point-to- multipoint Hello: 30 Wait: 120 Dead: 120

A and B