Day 13 - Single Area OSPF Implementation

Question 1

What is the first command to enter when enabling OSPF on a router with a process ID of 10?

Answer 1

router ospf 10

Question 2

What is the range of numbers that an OSPF process ID can be?

Answer 2

0 - 65535

Question 3

True or False:

The OSPF process ID has to match other OSPF routers to establish adjacencies with their neighbors?

Answer 3

False

This differs from EIGRP where the process ID and AS number must match to form adjacencies

Question 4

Put these steps in order of how a Cisco router chooses its router ID

1. If the router ID isn’t configured, the router chooses the highest IP address of any of its loopback interfaces
2. The router uses the IP address configured with the OSPF router-id command
3. If no loopback interfaces are configured, the router chooses the highest active IP address of any of its physical interfaces

Answer 4

2
1
3

Question 5

What commands would you use to verify or view the Router ID?

Answer 5

show ip ospf int
show ip protocols
show ip ospf

Question 6

Configure a Router ID based on this topology using 1.1.1.1, 2.2.2.2 and 3.3.3.3 matching up with the routers while using a process ID of 10

Answer 6

R1
router ospf 10
router-id 1.1.1.1

R2
router ospf 10
router-id 2.2.2.2

R3
router ospf 10
router-id 3.3.3.3

Question 7

True or False:

You should configure the router ID manually before invoking OSPF

Answer 7

True

Question 8

If you do not configure manual router IDs and then want to after enabling OSPF, what command can you use to reset OSPF to pick up the changes?

Answer 8

clear ip ospf process

Question 9

An __________ __________ is a group of routers that share link-state information

Answer 9

OSPF Area

Question 10

All OSPF routers in the same area must have the same __________ __________ __________ in their link-state databases

Answer 10

Link state information

Question 11

In the topology shown for R1, instead of targeting a network address, what commands could you use to directly target the interfaces 172.16.1.1, 172.16.3.1 and 192.168.10.5 and enable them for OSPF with a process ID of 10?

Answer 11

router ospf 10
network 172.16.1.1 0.0.0.0 area 0
network 172.16.3.1 0.0.0.0 area 0
network 192.168.10.5 0.0.0.0 area 0

Question 12

In the topology shown for R2, in targeting network addresses, what commands could you use to directly target the networks of 172.16.2.0. 172.16.3.0 and 192.168.10.8 and enable them for OSPF with a process ID of 10?

Answer 12

router ospf 10
network 172.16.2.0 0.0.0.255 area 0
network 172.16.3.0 0.0.0.3 area 0
network 192.168.10.8 0.0.0.3 area 0

Question 13

In the topology shown for R3, in targeting network addresses, what commands could you use to directly target the networks 192.168.1.0, 192.168.10.4 and 192.168.10.8 and enable them for OSPF with a process ID of 10?

Answer 13

router ospf 10
network 192.168.1.0 0.0.0.255 area 0
network 192.168.10.4 0.0.0.3 area 0
network 192.168.10.8 0.0.0.3 area 0

Question 14

By default, OSPF __________ are forwarded out all OSPF-enabled interfaces

Answer 14

Messages

Question 15

Which interfaces do not need to be privy to the OSPF process?

Answer 15

Gi0/0 on every router

Question 16

What commands would you use to make Gi0/0 a passive interface on R1, R2 and R3?

Answer 16

router ospf 10
passive-interface gi0/0

Question 17

What the is default OSPF cost value for a 10 Gig interface?

Answer 17

1

Question 18

What the is default OSPF cost value for a 1 Gig interface?

Answer 18

1

Question 19

What the is default OSPF cost value for a 100Mbps (FA) interface?

Answer 19

1

Question 20

What the is default OSPF cost value for a 10Mbps (Ethernet) interface?

Answer 20

10

Question 21

What the is default OSPF cost value for a T1 interface?

Answer 21

64

Question 22

As a matter of policy you should change the __________ __________ to accommodate networks with links faster than 100Mbps (100,000,000 bps)

Answer 22

Reference bandwidth

Question 23

What is the command to change the reference bandwidth within the OSPF router?

Answer 23

router ospf 10
auto-cost reference bandwidth {Mbps}

Question 24

What is the maximum OSPF cost for a Cisco router interface?

Answer 24

65535

Question 25

What is the most advantageous command you could use to alter the cost of an OSPF interface?

Answer 25

ip ospf cost {cost}

Question 26

What 3 generic commands could you use to verify OSPF as well as any other routing protocol?

Answer 26

show ip int brief
show ip route
show ip protocols

Question 27

What command would you use to verify neighbor adjacency in OSPF?

Answer 27

show ip ospf neighbor

Question 28

What command is the quickest way to verify OSPF interface settings such as process ID, area, ip addresses, cost, neighbors, etc

Answer 28

show ip ospf int brief