HPE6-A73 Exam - Question 77

Question

Examine the network topology.

The network is configured for OSPF with the following attributes:

✑ Core1 and Core2 and ABRs

✑ Area 1 has 20 networks in the 10.1.0.0/16 range

✑ Area 0 has 10 networks in the 10.0.0.0/16 range

✑ Area 2 has 50 networks in the 10.2.0.0/16 range

✑ The ASBR is importing a static route into Area 1

✑ Core2 has a summary for Area 2: area 0.0.0.2 range 10.2.0.0/16 type inter-area

Here is the OSPF configuration performed on Core1:

Based on the above information, what is correct?

Examice · Accepted Answer

ISP 1 is not reachable from any area. Area 0 is defined as a stub area, which means it does not accept or generate external routes and advertisements, specifically Type 5 LSAs, which are needed for inter-area routes to be known. Therefore, Core1 will not receive a Type 5 LSA from the ASBR. Since Core2 has a summary for Area 2, which is inter-area, and Area 1 is in a stub area, ISP 1 is not reachable from any area due to the stub configuration that prevents external routes from being advertised into the area.

spillo3000 · Answer

ISP 1 is not reachable from any area

E_Nick · Answer

To eliminate external routes and advertisements from an area, define the area as a stub area.

SeidorBruno · Answer

Page 395 Study Guide:
To   e l i m i n a t e   e x t e r n a l   r o u t e s   a n d   a d v e r t i s e m e n t s   f r o m   a n   a r e a ,   d e f i n e   t h e   a r e a   a s   a   s t u b   a r e a .  ABRs for stub areas do not forward Type 4 or Type 5 LSAs into those areas, and internal routers in those areas do not generate or accept them. 
[Aruba Networks]

theklee · Answer

Stub area does not allow type 5 LSA or ASBR. Answer is A, ISP cannot be reached by any area

Alialo · Answer

i would like to choose D, but not totally sure about that.
ASBR importing a static route into Area 1, not LSA5. 
20 local+1 LSA3+1 Static from ASBR+1 default from Area 0= 23 routes

theklee · Answer

Stub area does not allow type 5 LSA or ASBR

SahilERT · Answer

ISP can reach out to area1 via default route. Correct option D

johnhenri · Answer

A is correct: From learning book ACSP "Advanced OSPF" : "Internal routers in stub area : Do not support route redistribution (local external routes). ABRs for stub area : Suppress Type 5 LSAs (external route from other areas) & inject a default route"
B is incorrect because ABRs for stub area : Suppress Type 5 LSAs
C is incorrect because there is ABR route aggregation configuration for core1 area 1 & core2 area 2

HPE6-A73 Exam - Question 77

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