Given the following output, which statements can be determined to be true? (Choose three.)
RouterA2# show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
192.168.23.2 1 FULL/BDR 00:00:29 10.24.4.2 FastEthernet1/0
192.168.45.2 2 FULL/BDR 00:00:24 10.1.0.5 FastEthernet0/0
192.168.85.1 1 FULL/- 00:00:33 10.6.4.10 Serial0/1
192.168.90.3 1 FULL/DR 00:00:32 10.5.5.2 FastEthernet0/1
192.168.67.3 1 FULL/DR 00:00:20 10.4.9.20 FastEthernet0/2
192.168.90.1 1 FULL/BDR 00:00:23 10.5.5.4 FastEthernet0/1
<<output omitted>>
A.
This router is the DR for subnet 10.1.0.0.
B.
The DR for the network connected to Fa0/0 has an interface priority greater than 2.
C.
The DR for the network connected to Fa0/1 has a router ID of 10.5.5.2.
D.
The DR for the serial subnet is 192.168.85.1.
E.
This router is neither the DR nor the BDR for the Fa0/1 subnet.
F.
RouterA2 is connected to more than one multi-access network.
Explanation:
The show ip ospf neighbor command displays a list of all OSPF routers with which you have established a neighbor relationship. The following describes the
command output:
Neighbor ID: the Router ID (RID) of the neighboring router
Pri: the interface priority of the neighboring router, which is used to determine which router should serve the function of a Designated Router (DR)
State: the functional state of the neighboring router
Dead Time: the period that the router will wait to hear a Hello packet from this neighbor before declaring the neighbor down
Address: the IP address of the neighboring router on this subnet
Interface: the local interface over which the neighbor relationship (adjacency) was formed
The output for neighbor 192.168.45.2 is as follows:
192.168.45.2 2 FULL/BDR 00:00:24 10.1.0.5 FastEthernet0/0
This indicates that the interface priority of neighbor 192.168.45.2 is 2. The default OSPF interface priority is 1, and the highest interface priority determines the
designated router (DR) for a subnet. This same line reveals that this neighbor is currently the backup designated router (BDR) for this segment, which indicates that
another router became the DR. It can be then be assumed that the DR router has an interface priority higher than 2. (The router serving the DR function is not
present in the truncated sample output.)
The output for the two neighbors discovered on F0/1 is as follows:
192.168.90.3 1 FULL/DR 00:00:32 10.5.5.2 FastEthernet0/1
192.168.90.1 1 FULL/BDR 00:00:23 10.5.5.4 FastEthernet0/1
This output indicates that router 192.168.90.3 is the DR, and router 192.168.90.1 is the BDR for this network. Since there can only be one DR and BDR per
segment, this indicates that the local router is neither the DR nor the BDR. (OSPF considers these DROther routers.)
The fact that multiple DRs are listed in this output indicates that RouterA2 is connected to more than one multi-access segment, since each segment will elect a DR.
It cannot be determined if this router is the DR for subnet 10.1.0.0. The output indicates that router 192.168.45.2 is the BDR for this network, but with the truncated
output, it cannot be determined if this router is the DR.The DR for the network connected to Fa0/1 does not have a router ID of 10.5.5.2. The Address field of the show ip ospf neighbor command indicates the IP address
of the neighbor’s interface, not the router ID of the neighbor.
The DR for the serial subnet is not 192.168.85.1, since point-to-point serial interfaces do not elect DRs and BDRs. This is indicated by the output below:
192.168.85.1 1 FULL/- 00:00:33 10.6.4.10 Serial0/1
Objective:
Routing Fundamentals
Sub-Objective:
Configure, verify, and troubleshoot single area and multi-area OSPFv2 for IPv4 (excluding authentication, filtering, manual summarization, redistribution, stub,
virtual-link, and LSAs)Cisco > Support > IP > IP Routing > Technology Information > Technology White Paper > OSPF Design Guide > Document ID: 7039 > DR Election