Exam 350-401 topic 1 question 428 discussion

C is correct

there two route-maps configured one with AS prepend which will influence the traffic inbound to R1

Exported routes from R1 should be advertised with AS path prepend to ISP2, to make it less preferred. This is the same way as the incoming routes coming with a longer AS path by ISP2. The 3 ASs 65000 in the incoming routes is to mislead us.

C is correct. Change the bgp neighbor setting to out instead of in for ISP2 to influence the routes sent to ISP2 to make the routing less preferred.

C is the correct answer. R1 makes ISP2 less preferenced by adding more AS path to its best path advertisement. prepended AS path is transitive and the upstream will choose the lesser AS path as the best path which is ISP1 to reach R1.

as I got it, from AS 64500 (not shown in the map but you see it in as path) point of view after "answer C" 3 hops were added to the as path towards ISP2 and ISP2 propagates this info further, so as64500 chooses the shortest path with 3 hops compare to six, agree? :))

The Answer is C, correct.

when I am not sure like I am now I go for exclusion, D is out of the question since local preference has only affect locally, then B is also out because the ACL would again have affect only on the local router and because we are setting weight to 100, the weight on the link toward ISP1 is still better as the weight is 200, therefore a null change there. A and C remain as contendents, and the weight change makes sense but because we are trying to influence ISP2 path choice, C accually has a better method by prepending 3 extra hops to the path, so to me it looks like C makes the most sense.

Is C is the correct answer?