OSPF

Question 1

what type of routing protocol is OSPF

Answer 1

Link-state

Question 2

OSPF algorithm

Answer 2

Dijkstra

Question 3

What metric does OSPF use

Answer 3

Cost

Question 4

AD for OSPF

Answer 4

110

Question 5

IP transport used for OSPF

Answer 5

88

Question 6

OSPF authenitcation

Answer 6

MD5

Question 7

ALL routers broadcast address

Answer 7

224.0.0.5

Question 8

DR routers broadcast address

Answer 8

224.0.0.6

Question 9

OSPF cost calculation

Answer 9

ref bw / int bw (100 / 10mb)

Question 10

OSPF adj states (8) (d,a,i,2,ex,ex,L,F)

Answer 10

down, attempt, init, 2-way, exstart, exchange, loading, full

Question 11

LSA type 1

Answer 11

Router link - lists neighboring routers and cost, flooded within an area

Question 12

LSA type 2

Answer 12

Network link - Gen by DR, lists adj area routers, flooded within an area

Question 13

LSA type 3

Answer 13

Network summary - Gen by ABR, advertised among areas

Question 14

LSA type 4

Answer 14

ASBR summary - injected by ABR into backbone to advertise presence of ASBR

Question 15

LSA type 5

Answer 15

Gen by ASBR and flooded throughout AS to advertise route external to OSPF (rip or eigrp or bgp areas)

Question 16

LSA type 7

Answer 16

Gen by ASBR in not-so-stubby-area. converted to type-5 by ABR when leaving the area.

Question 17

Internal Router

Answer 17

All interfaces exist in the same area

Question 18

Backbone Router

Answer 18

has an interface in Area 0

Question 19

ABR

Answer 19

Area Border Router - connects two or more areas

Question 20

ASBR

Answer 20

AS Boundary Router - connects to other routing domains (bgp, rip, eigrp)

Question 21

Stub area

Answer 21

External LSA-type 5’s are replaced with a default route

Question 22

Totally stubby area

Answer 22

type 3,4,5 are replaced with a default route

Question 23

Not so stubby area

Answer 23

stub area containing an asbr, type 5 are converted to type 7 within the area

Question 24

OSPF external route type - E1

Answer 24

cost to the ASBR plus external cost of the route

Question 25

OSPF external route type - E2

Answer 25

default - cost of route as seen by ASBR

Question 26

Hello/Dead timers for NBMA and multi-point

Answer 26

30/120

Question 27

Hello/Dead timers for broadcast and p2p

Answer 27

10/40

Question 28

OSPF neighborship requirements (a,a,s,t,s)

Answer 28

Match: area, auth, subnet, timers, stub

Question 29

OSPF stub gets rid of which route type?

Answer 29

O E2 (type 5 external) (networks redistributed in to OSPF, cost 20)

Question 30

What does OSPF total stub area do for routing?

Answer 30

Causes all internal and external routes to use a default route to exit the total stub area. Configured on the upstream ABR, not on the TS router. Stops type 3,4,5 LSA’s.

Question 31

What is the criteria to form ospf neighborship (ANTP)

Answer 31

Area ID

Network mask

Timers

Authentication Password