350-401 OSPF Practice Test 2 — 15 Questions

Question 1

A network engineer runs the following command on Router R7:

R7# show ip ospf virtual-links

Virtual Link OSPF_VL0 to router 2.2.2.2 is up
  Run as demand circuit
  DoNotAge LSA allowed.
  Transit area 1, via interface GigabitEthernet0/1, Cost of using 10
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    Hello due in 00:00:07
  Adjacency State FULL

Based on this output, what can be concluded?

Accepted Answer

Router 2.2.2.2 is the other endpoint of the virtual link.. The output shows that the virtual link OSPF_VL0 to router 2.2.2.2 is up and the adjacency state is FULL. This confirms that router 2.2.2.2 is the remote endpoint of the virtual link, as the command displays the router ID of the neighbor at the other end of the virtual link.

Answer

The virtual link is used to connect area 0 to a non-backbone area.

Answer

The virtual link is down.

Answer

The virtual link uses area 0 as the transit area.

Question 2

A network engineer issues the following command on Router R8:

R8# show ip ospf neighbor detail

Neighbor 1.1.1.1, interface address 192.168.1.1
    In the area 0 via interface GigabitEthernet0/0
    Neighbor priority is 1, State is FULL, 6 state changes
    DR is 192.168.1.2, BDR is 192.168.1.1
    Options is 0x42 (L LSR LSRR L LSR)
    Dead timer due in 00:00:34
    Neighbor is up for 00:12:45
    Index 1/1/1, retransmission queue length 0, number of retransmission 0
    First 0x0(0)/0x0(0)/0x0(0) Next 0x0(0)/0x0(0)/0x0(0)
    Last retransmission scan length is 0, last retransmission scan time is 0 msec

Based on this output, what can be concluded?

Accepted Answer

Router 1.1.1.1 is the Backup Designated Router.. The output shows 'BDR is 192.168.1.1', which is the interface address of neighbor 1.1.1.1. This directly indicates that router 1.1.1.1 is the Backup Designated Router on this segment. The neighbor state is FULL, confirming adjacency is fully established.

Answer

Router 1.1.1.1 is the Designated Router on this segment.

Answer

The neighbor state is 2WAY.

Answer

The dead timer is 40 seconds.

Question 3

A network engineer runs the following command on Router R9:

R9# show ip ospf interface brief

Interface    PID   Area            IP Address/Mask    Cost  State Nbrs F/C
Gi0/0        1     0               192.168.1.9/24     10    DR    2/2
Gi0/1        1     1               10.0.0.9/24        20    BDR   1/1
Lo0          1     0               9.9.9.9/32         1     LOOP  0/0

Based on this output, what can be concluded?

Accepted Answer

R9 has two fully adjacent neighbors on Gi0/0.. The output shows that on interface Gi0/0, R9 has a state of DR (Designated Router) and 2 fully adjacent neighbors (Nbrs F/C = 2/2). The '2/2' indicates 2 neighbors in a full state out of 2 total neighbors, meaning both neighbors have completed the OSPF adjacency process. Therefore, R9 has two fully adjacent neighbors on Gi0/0, making option B correct.

Answer

R9 is the Designated Router on the segment connected to Gi0/1.

Answer

The loopback interface Lo0 is advertised as a /24 network.

Answer

R9 is an Area Border Router.

Question 4

Router R1 has the following OSPF configuration:

interface GigabitEthernet0/0
 ip address 10.1.1.1 255.255.255.0
 ip ospf 1 area 0
 ip ospf network point-to-point
!
router ospf 1
 router-id 1.1.1.1
 network 10.0.0.0 0.255.255.255 area 0

What is the effect of the 'ip ospf network point-to-point' command on this interface?

Accepted Answer

It changes the OSPF network type to point-to-point, eliminating DR/BDR election and reducing hello timer to 10 seconds.. The 'ip ospf network point-to-point' command changes the OSPF network type on the interface from the default (broadcast for Ethernet) to point-to-point. This eliminates the need for a Designated Router (DR) and Backup Designated Router (BDR) election, as point-to-point links have only two neighbors. Additionally, the OSPF hello timer on a point-to-point network defaults to 10 seconds (versus 30 seconds for non-broadcast), and the dead timer is 40 seconds.

Answer

It disables OSPF on the interface.

Answer

It enables OSPF authentication on the interface.

Answer

It sets the OSPF cost to 1.

Question 5

Consider the following OSPF configuration on router R2:

interface GigabitEthernet0/0
 ip address 192.168.1.2 255.255.255.0
 ip ospf 1 area 0
 ip ospf hello-interval 5
!
router ospf 1
 router-id 2.2.2.2
 network 192.168.1.0 0.0.0.255 area 0

Which statement is true about this configuration?

Accepted Answer

The OSPF dead interval is automatically set to 20 seconds.. The correct answer is A because the OSPF dead interval is automatically set to four times the hello interval when the hello interval is manually configured. By default, OSPF uses a hello interval of 10 seconds and a dead interval of 40 seconds on broadcast networks. However, when you explicitly set the hello interval to 5 seconds using the 'ip ospf hello-interval 5' command, the router automatically adjusts the dead interval to 20 seconds (4 × 5 seconds) to maintain the standard ratio, unless the dead interval is also manually configured.

Answer

The OSPF dead interval remains at the default of 40 seconds.

Answer

This configuration will cause OSPF to use MD5 authentication.

Answer

The OSPF network type changes to point-to-point.

Question 6

Router R3 has the following OSPF configuration:

router ospf 1
 router-id 3.3.3.3
 network 10.0.0.0 0.255.255.255 area 0
 default-information originate always metric 20 metric-type 2

What is the effect of the 'default-information originate always' command?

Accepted Answer

It injects a default route into OSPF unconditionally, with metric 20 and type E2.. The 'default-information originate always' command injects a default route (0.0.0.0/0) into the OSPF link-state database unconditionally, regardless of whether the router itself has a default route in its routing table. The 'always' keyword overrides the default behavior, which requires a pre-existing default route. The metric 20 and metric-type 2 (E2) are explicitly set in the command, making the injected route an external type 2 route with a seed metric of 20.

Answer

It redistributes all connected routes into OSPF.

Answer

It injects a default route into OSPF only if a default route is present in the routing table.

Answer

It sets the OSPF router ID to 3.3.3.3 and enables default route filtering.

Question 7

Examine this OSPF configuration on router R4:

interface GigabitEthernet0/0
 ip address 172.16.1.4 255.255.255.0
 ip ospf 1 area 0
 ip ospf cost 50
!
router ospf 1
 router-id 4.4.4.4
 network 172.16.0.0 0.0.255.255 area 0

What is the OSPF cost of the GigabitEthernet0/0 interface?

Accepted Answer

50. The OSPF cost of an interface is determined by the `ip ospf cost` command, which explicitly overrides the default cost calculation based on reference bandwidth. Since R4's GigabitEthernet0/0 interface has `ip ospf cost 50` configured under it, the cost is set to 50 regardless of the interface bandwidth or reference bandwidth settings.

Answer

1 (default for GigabitEthernet)

Answer

100 (derived from reference bandwidth 100 Mbps / 1 Gbps)

Answer

10 (derived from reference bandwidth 1000 Mbps / 100 Mbps)

Question 8

Router R5 has the following OSPF configuration:

router ospf 1
 router-id 5.5.5.5
 network 10.0.0.0 0.255.255.255 area 0
 area 0 authentication message-digest
!
interface GigabitEthernet0/0
 ip address 10.1.1.5 255.255.255.0
 ip ospf message-digest-key 1 md5 cisco123

What is missing from this OSPF authentication configuration?

Accepted Answer

The interface needs the 'ip ospf authentication message-digest' command.. Option B is correct because OSPF authentication configuration requires two components: an area-level authentication type (configured via `area 0 authentication message-digest`) and an interface-level authentication mode (configured via `ip ospf authentication message-digest`). The interface command tells the OSPF process to actually use the key defined with `ip ospf message-digest-key`. Without it, the interface defaults to no authentication, even though the area is configured for authentication.

Answer

The configuration is complete and correct.

Answer

The 'area 0 authentication' command should be 'area 0 authentication md5'.

Answer

The 'network' command should include the area authentication keyword.

Question 9

Router R6 has the following OSPF configuration:

router ospf 1
 router-id 6.6.6.6
 network 192.168.0.0 0.0.255.255 area 0
 passive-interface default
 no passive-interface GigabitEthernet0/0
!
interface GigabitEthernet0/0
 ip address 192.168.1.6 255.255.255.0
 ip ospf 1 area 0

What is the effect of the 'passive-interface default' command?

Accepted Answer

Only GigabitEthernet0/0 is active; all other OSPF interfaces are passive.. The 'passive-interface default' command sets all OSPF interfaces to passive by default, meaning they will not send or receive OSPF hello packets and thus cannot form adjacencies. The subsequent 'no passive-interface GigabitEthernet0/0' overrides this for that specific interface, making it the only active OSPF interface. This matches option B.

Answer

All OSPF interfaces become passive, including GigabitEthernet0/0.

Answer

OSPF adjacencies are formed on all interfaces.

Answer

The 'passive-interface default' command is ignored because the 'network' command is used.

Question 10

What is the default OSPF hello interval on a broadcast multi-access network (e.g., Ethernet)?

Accepted Answer

10 seconds. On broadcast multi-access networks like Ethernet, OSPF defaults to a hello interval of 10 seconds. This is defined in RFC 2328 and is used to maintain neighbor relationships and detect failures quickly. The corresponding dead interval is 40 seconds (4 times the hello interval).

Answer

5 seconds

Answer

30 seconds

Answer

40 seconds

Question 11

In OSPF, which LSA type is used to describe routes to networks within the same area and is generated by the router that owns the network?

Accepted Answer

Type 1 (Router LSA). Type 1 (Router LSA) is correct because each OSPF router generates a Type 1 LSA to describe its directly connected links and networks within the same area. This LSA is flooded only within the originating area and is the fundamental building block for intra-area route calculation using the SPF algorithm.

Answer

Type 2 (Network LSA)

Answer

Type 3 (Summary LSA)

Answer

Type 5 (External LSA)

Question 12

What is the default OSPF reference bandwidth used for cost calculation in Cisco IOS?

Accepted Answer

100 Mbps. In Cisco IOS, the default OSPF reference bandwidth is 100 Mbps. OSPF calculates the cost of an interface as the reference bandwidth divided by the interface bandwidth. With the default reference of 100 Mbps, a FastEthernet (100 Mbps) interface gets a cost of 1, which is the minimum cost. This default was established when FastEthernet was considered high-speed, but it can be changed using the 'auto-cost reference-bandwidth' command to accommodate faster links like GigabitEthernet.

Answer

1000 Mbps

Answer

10 Mbps

Answer

1 Mbps

Question 13

Drag and drop the steps of OSPF neighbor adjacency formation into the correct order, from first to last.

Accepted Answer

Router sends Hello packets on interface. OSPF neighbors transition through Down, Init, 2-Way, ExStart, Exchange, Loading, and Full states. The correct order begins with the router sending Hello packets (Down to Init), then receiving a Hello reply (Init to 2-Way), electing DR/BDR if needed (2-Way to ExStart), exchanging database description packets (ExStart to Exchange), and finally synchronizing databases (Loading to Full).

Question 14

Drag and drop the steps of OSPF route redistribution into a different autonomous system into the correct order, from first to last.

Accepted Answer

Configure OSPF process on the ASBR. Redistribution requires first configuring the routing process that will receive the routes, then defining the source protocol and metric, optionally setting route tags for loop prevention, applying a route map for filtering, and finally verifying the redistributed routes appear in the OSPF database.

Question 15

Drag and drop the steps of OSPF virtual link configuration into the correct order, from first to last.

Accepted Answer

Identify the ABR in the transit area. A virtual link connects a non-backbone area to Area 0 through a transit area. First, identify the ABR with the transit area, then configure the virtual link on both ABRs using the router ID of the neighbor, ensure the transit area has full OSPF adjacency, and finally verify the virtual link is operational.