Case study.
 
Some notices from above configuration:
+The OSPF network type between R2&R3 is non broadcast.
Q1: Show ip ospf database -
Q2: Show ip ospf interface serial 1/0
Q3: Show ip ospf -
Q4: Show ip route -
You have been asked to evaluate an OSPF network and to answer questions a customer has about its operation. Note: You are not allowed to use the show command. running-config
 
Although in this sim we are not allowed to use "show running-config" command but we post the configuration here so that you can understand more about the topology.
R1 -
interface Loopback0
ip address 1.1.1.1 255.255.255.255
no shut
interface Serial0/0
ip address 192.168.13.1 255.255.255.0
ip ospf network non-broadcast
no shut
router ospf 1
network 192.168.13.0 0.0.0.255 area 0
network 1.1.1.1 0.0.0.0 area 0
_______________________________________
R2 -
interface Loopback 0
ip address 2.2.2.2 255.255.255.255
no shut
interface S0/0
ip address 192.168.23.2 255.255.255.0
ip ospf network non-broadcast
no shut
router ospf 1
network 192.168.23.0 0.0.0.255 area 0
network 2.2.2.2 0.0.0.0 area 0
neighbor 192.168.23.3
_________________________________________________
R3 -
interface Loopback 0
ip address 3.3.3.3 255.255.255.255
no shut
interface fa0/0
ip address 192.168.34.3 255.255.255.0
no shut
interface S0/1
ip address 192.168.23.3 255.255.255.0
ip ospf network non-broadcast
no shut
interface S0/0
ip address 192.168.13.3 255.255.255.0
ip ospf network non-broadcast
no shut
router ospf 1
network 192.168.13.0 0.0.0.255 area 0
network 192.168.23.0 0.0.0.255 area 0
network 192.168.34.0 0.0.0.255 area 1
network 3.3.3.3 0.0.0.0 area 0
area 1 virtual-link 4.4.4.4
neighbor 192.168.23.2
_______________________________________________________________
R4 -
interface Loopback 0
ip address 4.4.4.4 255.255.255.255
interface FastEthernet0/0
ip address 192.168.34.4 255.255.255.0
interface Fa0/1
ip address 192.168.45.4 255.255.255.0
no shut
interface Fa1/0
ip address 192.168.46.4 255.255.255.0
no shut
router ospf 1
network 192.168.34.0 0.0.0.255 area 1
network 192.168.45.0 0.0.0.255 area 2
network 192.168.46.0 0.0.0.255 area 3
network 4.4.4.4 0.0.0.0 area 1
area 1 virtual-link 3.3.3.3
area 2 nssa
area 3 stub no-summary
_________________________________________________________________
R5 -
interface Loopback0
ip address 5.5.5.5 255.255.255.255
interface Loopback1
ip address 5.5.1.1 255.255.255.255
interface Loopback2
ip address 5.5.2.1 255.255.255.255
interface Loopback3
ip address 5.5.3.1 255.255.255.255
interface Loopback4
ip address 5.5.4.1 255.255.255.255
no shut
interface Fa0/0
ip address 192.168.45.5 255.255.255.0
no shut
router ospf 1
network 192.168.45.0 0.0.0.255 area 2
network 5.5.0.0 0.0.255.255 area 2
area 2 nssa
_______________________________________________
R6 -
interface Fa0/0
ip address 192.168.46.6 255.255.255.0
no shut
interface Loopback 0
ip address 6.6.6.6 255.255.255.255
no shut
router ospf 1
network 192.168.46.0 0.0.0.255 area 3
network 6.6.6.6 0.0.0.0 area 3
area 3 stub
Areas of Router 5 and 6 are not normal areas, inspect their routing tables and determine which statement is true?

A. R5"²s Loopback and R6"²s Loopback are both present in R5"²s Routing table

B. R5"²s Loopback and R6"²s Loopback are both present in R6"²s Routing table

C. Only R5"²s loopback is present in R5"²s Routing table

D. Only R6"²s loopback is present in R5"²s Routing table

E. Only R5"²s loopback is present in R6"²s Routing table






 

Suggested Answer: A

Area 2 (of R5) is a Not-so-Stubby area (NSSA). You can check it by the "show ip ospf" command on R4 or R5 (in Area 2 section). For example, below is the output of "show ip ospf" command on R5:
 <img src="https://www.examtopics.com/assets/media/exam-media/02670/0045900001.jpg" alt="Reference Image" />
In general, NSSA is same as normal area except that it can generate LSA Type 7 (redistribute from another domain) so we can see both Loopback interfaces of
R5 & R6 in the routing table of R5.
 <img src="https://www.examtopics.com/assets/media/exam-media/02670/0046000001.jpg" alt="Reference Image" />
Note: NSSA does not receive a default route by default so you will not see a default route on R5.
Area 3 (of R6) is a Totally-Stubby area so R6 only has one default route to outside world. You can check with the "show ip ospf" command on R4 and R6 (area 3 section):
 <img src="https://www.examtopics.com/assets/media/exam-media/02670/0046100001.jpg" alt="Reference Image" />
 <img src="https://www.examtopics.com/assets/media/exam-media/02670/0046200001.png" alt="Reference Image" />
Notice that on R4 you will get more detail (shows "stub area, no summary LSA") than on R6 (only shows "stub area").
R6 is in a totally-stubby area so we will not see any R5's Loopback interfaces in R6 routing table:
 <img src="https://www.examtopics.com/assets/media/exam-media/02670/0046300001.jpg" alt="Reference Image" />
Note: You can see a default (summary) route to the outside (O*IA 0.0.0.0/0 "¦)
Even though this exercise looks complicated, it can be solve with simple commands:
Q1: show ip ospf database -
Q2: show ip ospf database int s0/1
Q3: Show ip ospf -
Q4: show ip ospf and show ip route

This question is in 300-101 Cisco Implementing Cisco IP Routing (ROUTE) Exam
For getting Cisco Certified Network Professional (CCNP) Routing and Switching Certificate




Disclaimers:
The website is not related to, affiliated with, endorsed or authorized by Cisco.
Trademarks, certification & product names are used for reference only and belong to Cisco.
The website does not contain actual questions and answers from Cisco's Certification Exam.