Exam 300-420 topic 1 question 197 discussion

Actual exam question from Cisco's 300-420

Question #: 197
Topic #: 1

Refer to the exhibit. An architect is designing a hierarchical ISIS solution for a customer with these requirements:
• Routers will double in all areas within the next 24 months.
• Link flaps within areas 20 and 30 must not impact the backbone area.
• Traffic originating from A201 and A302 routers must connect to application servers in the backbone.

Which design must the architect select?

A. C101 Level 1/2, A201 Level 1, and A101 Level 2
B. C201 Level 1/2, A301 Level 1/2, and A102 Level 1/2
C. C302 Level 2, A302 Level 1/2, and A101 Level 2
D. C102 Level 2, A202 Level 2, and A102 Level 1

Show Suggested Answer

Suggested Answer: A 🗳️

by cerifyme85 at April 14, 2023, 5:52 a.m.

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cerifyme85

Highly Voted 1 year, 8 months ago

Selected Answer: A

OCG Book says: An L2 router is similar to an OSPF backbone router. A router that has both Level 1 and 2 routes is similar to an OSPF area border router (ABR). IS-IS does not define a backbone area like OSPF’s area 0, but you can consider the IS-IS backbone a continuous path of adjacencies among Level 2 ISs. Answer A

upvoted 10 times

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jahax

Most Recent 4 months, 3 weeks ago

Selected Answer: A

To met requirement for flaps in area 20/30 we need to ensure that A2xx/A3xx routers are L1 only. Backbone ideally should consist only L2 rotuers but L2/L1 is also acceptable - seems to most accurate A.

upvoted 1 times

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26d13e9

7 months, 3 weeks ago

The most stupid question of all time

upvoted 3 times

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mgiuseppe86

1 year, 1 month ago

How can A be the answer when C201 is L1 in A20 it will never talk to C101 in A0 because L1 routers cant form adjacencies with L1/L2 routers in a different area. This question is stupid B is the only answer that makes sense

upvoted 1 times

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