OSPF

Question 1

What algorithm does OSPF use to choose best path ?

Answer 1

Dijkstra’s algorithm

Question 2

What is the metrics used in determining what route gets installed in the routing table ?

Answer 2

Administrative Distance

Question 3

What is the Administrative Distance of OSPF ?

Answer 3

110

Question 4

OSPF Packet types

Answer 4

hello, database description, request, update, acknowledgement

Question 5

What hello packets are used for ?

Answer 5

Establish neighbor adjacencies

Question 6

Single - Area OSPF

Answer 6

Routers are contained in one area
backbone area
known as area 0
in smaller networks with few routers

Question 7

Multiarea OSPF

Answer 7

Use hierarchical scheme
Areas connected to area 0
Used in large networks

Question 8

Why have a DR/DBR election ?

Answer 8

Reduce the no of adjacencies over a multi-access network like Ethernet
Reduce no. of LSAs sent

Question 9

Used to identify an OSPF router

Answer 9

Router IDs

Question 10

What if no router ID is configured ?

Answer 10

Highest configure loopback interface is used

Question 11

No configured loopback interfaces to identify router id

Answer 11

Highest active IPv4 address is used

Question 12

Command to verify the router ID

Answer 12

show ip protocols

Question 13

A command that does not send OSPF messages.

Answer 13

Passive interface

Question 14

cost of 10 Gbps Ethernet

Answer 14

1

Question 15

100 Mbps Ethernet

Answer 15

1

Question 16

1 Gbps Ethernet

Answer 16

1

Question 17

Concept of OSPF Metric = Cost

Answer 17

lower bandwidth interface has a higher cost

Question 18

Adjusting reference bandwidth

Answer 18

auto cost reference-bandwidth 10000

Question 19

Multiarea OSPF

Answer 19

Reduces processing and memory overhead

Question 20

What is used to create the OSPF neighbor table?

Answer 20

adjacency database

Question 21

A router that has interfaces attached to multiple areas

Answer 21

Area Border Router (ABR)

Question 22

A router in the backbone area, Set to 0

Answer 22

Backbone Router

Question 23

A router that has all of its interfaces in the same area

Answer 23

Internal router

Question 24

A router that has at lease one interface attached to an external internetwork

Answer 24

Autonomous System Boundary Router (ASBR)

Question 25

advertising external (non-OSPF) network addresses

Answer 25

LSA Type 5

Question 26

advertising networks from other areas by ABRs

Answer 26

LSA Type 3

Question 27

including a list of directly attached network prefixes and link type

Answer 27

LSA Type 1

Question 28

identifying the routers and the network address of the multiaccess link

Answer 28

LSA Type 2

Question 29

advertising an ASBR to other areas and providing a route to it

Answer 29

LSA Type 4

Question 30

LSA type is flooded by a designated router to other OSPF routers within the same area?

Answer 30

LSA Type 2

Question 31

What information is advertised in a type 4 LSA?

Answer 31

the route to reach an ASBR

Question 32

What is used to facilitate hierarchical routing in OSPF?

Answer 32

the use of multiple areas

Question 33

what does IA mean

Answer 33

IA mean OSPF routing information learnt via routers from Inter-area

Question 34

Which router summaries all the internal routes in the internal networks into the backbone area.

Answer 34

ABRs

Question 35

What is the different between static & dynamic routing protocols and where it is used

Answer 35

Stub-Network or Open internet