OSPF Routing Protocol Q/A's

Question 1

OSPF uses link cost and speed to calculate it’s routing metric? True / False

What does OSPF stand for?

Answer 1

True

Open Shortest Path First

Question 2

What type of advertisement does OSPF use to pass routing updates?

Answer 2

(LSA) Link State Advertisements

Question 3

In what order does OSPF Operate from 1 - 6?

Discover What?
Form What?
Flood What?
Compute What?
Install What?
Respond to What?

Answer 3

1. Discover Neighbors
2. Form Adjacencies
3. Flood Link State Database (LSDB)
4. Compute Shortest Path
5. Install best routes in the routing table
6. Respond to network changes

Question 4

What do Link State Advertisements LSA advertise?

Answer 4

routing updates

Question 5

What are Link State Updates responsible for exchanging?

Answer 5

topology information

Question 6

What identifies a router using OSPF?

Answer 6

router id

Question 7

What is the cost of OSPF actually derived from?

Answer 7

bandwidth/interface bandwidth

Question 8

What is the default cost on “All OSPF” routers?

Answer 8

1

Question 9

When making changes to OSPF it is recommended to modify the cost not what?

Answer 9

bandwidth

Question 10

Hello interval is the time in which, what are sent out?

Answer 10

hello packets

Question 11

What is a dead interval?

Answer 11

Time in which router is declared out of service.

Question 12

The router priority is used to select what types of routers for OSPF?

Answer 12

(DR) and (BDR)

Designated Router & Backup Designated Router

Question 13

What must match for OSPF to form an adjacency?

Same two what?
What two intervals?
What subnet?
What type of flag?
What type of area flag?

Answer 13

Same area and network 
Hello and dead intervals
IP subnet
authentication flag
stud area flag

Question 14

The DR and BDR establishes a full neighbor state with all routers on the network segment. True of False

The neighbor state on other neighbors remain in what state, and do not exchange what with each other?

Answer 14

true

2-way state and do not exchange routes

Question 15

What is the Designated Router multicast IP address for (all ospf routers)

Answer 15

224.0.0.5

Question 16

Routers in their OSPF area maintain full or summary information about it’s own area?

Routers in other OSPF area maintain full or summary information about other areas?

Answer 16

Full information

Summary information

Question 17

What do backbone routers maintain for each area and links in their own area?

Answer 17

Full Link State Databases (LSDB)

Question 18

An ABR Area Border Router is used to connect to what on a OSPF network?

Answer 18

one or more areas to the main backbone

Question 19

It is ideal to have each ABR connected to how many areas only?

Answer 19

two

Question 20

What is area ID?

Answer 20

Area configured in an OSPF network

Question 21

Do ABR’s automatically summarize routes?

What would happen if ABR’s routers were not summarized?

Answer 21

No

All routes would be flooded everywhere

Question 22

An External AS in OSPF is used in an Autonomous System Boundary Routers (ASBR) to do what?

Answer 22

advertise external routing information throughout the AS

Question 23

Do routers use the lowest or highest IP address with longest or shortest prefix to elect the router ID?

Answer 23

highest IP address with longest prefix

Question 24

OSPF is what kind of routing protocol?

Answer 24

Link State