Refer to the exhibit. IS-IS is the routing protocol on the network. After the team noticed excessive CPU usage on all routers, particularly routers R2 and R6, they configured route summarization on all routers. However, a network engineer noticed that summary routes and more specific routes are present in the routing table on R1. Which action must the team take so that R1 receives only the summary routes?
To ensure that R1 receives only summary routes, it is necessary to configure summarization on routers that are responsible for routing between different areas. R3 and R5 are the Area Border Routers (ABRs) between Area 1 and Area 2 and can perform summarization for both Level 1 and Level 2 routers. This will help summarize routes from one area to another, reducing the routing information passed to R1 and thus ensuring that R1 receives only the summary routes.
After thinking on it, this must be A, they specifically call out routers 2 and 6 as having issues, by summarizing level 1 routes from area 2 to area 1 we can fix R2. If we also summarize on R3/R5 towards R6 for level 2 routes we can fix it as well.
I think so too, but the question that needs to be answered is "action must the team take so that R1 receives only the summary routes", thereby ignoring the fact that R2 and R6 have high utilization.
You can only configure summarization between areas or on a router that is doing redistribution. So if there is not any redistribution on R2/R4 you can not do summarization there.
R2 and R4 are ABRs between Area 1 and Area 2, so not sure why they wouldn't be able to summarize. Either way I'm not sure of a good answer here