Exam 300-510 topic 1 question 131 discussion

Actual exam question from Cisco's 300-510

Question #: 131
Topic #: 1

Refer to the exhibit. Routers R2, R3, R4, and R5 all reside in the same area, with R1 in a different area. R3 is overutilized, and the engineer wants to reduce its CPU load. The engineer configured router R4 to summarize routes that it receives from R5, but R3 is still receiving all of the R5 routes. Which action resolves the issue?

A. Configure the summary routes on R5.
B. Configure R4 as a Level 1-Level 2 router.
C. Configure R2 as a Level 1 router.
D. Configure R3 in a new area.

Show Suggested Answer

Suggested Answer: D 🗳️

by jospinales at Oct. 17, 2023, 6:17 p.m.

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serban_17

9 months ago

We need more info on the level of other routers: A - if the routes are redistributed B - if R5 is level-1 (summarization of L1 routes entering L2) C - if R1 and R3 are also L1 (summarization of L2 routes leaked into L1) D - it will never work (if R3 is L1, the isis will not come up, if it is L2 or L1/L2 it must receive everything to have the L2 LSDB synced)

upvoted 1 times

serban_17

9 months ago

D actually might work if R3 is L2, summarization is done on R2 and R4, R5 are L1 (we have again summarization of L1 routes entering L2)

upvoted 1 times

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DUsoo

10 months, 1 week ago

You can only configure summarization on a “border”. That would be an area border router or a router that is doing redistribution. A. Configure the summary routes on R5. --> Yes it make sense if we do redistribution of routes to IS-IS. But this is not specified in Q. B. Configure R4 as a Level 1-Level 2 router --> this will not help as R4 is in the same area and it's not border router. C. Configure R2 as a Level 1 router --> will not help. D. Configure R3 in a new area. --> Yes, you can do that, but then you have to do summarization on router R2, but we do not have this option in Q. So according to me the best option is option A.

upvoted 1 times

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jospinales

1 year, 2 months ago

Selected Answer: B

Redistribution must be done on L1/L2 routers, so you could summarize the routes on R2 or change router R4 as an L1/L2.

upvoted 2 times

Storcaks

11 months, 2 weeks ago

B is not correct. The routes will still be leaked as level 1 routes as all routers are in the same area except R1. The only choice that will work is D. If R3 is configured as level 1, which we have to assume from the exhibit, and changed into a new area it will stop receiving is-is routes completely from the other routers.

upvoted 2 times

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