Refer to the exhibit.
 
A Boston company bought the assets of a New York company and is trying to route traffic between the two data networks using EIGRP. The show command output shows that traffic will not flow between the networks. As a network consultant, you were asked to modify the configuration and certify the interoperability of the two networks. For traffic to flow from subnet 172.16.8.0/24 to the 172.16.16.0/24 subnet.
Which configuration change do you recommend?

A. Turn off autosummarization on routers N1 and B1.

B. Add IP summary addresses to the Internet-pointing interfaces of routers N1 and B1.

C. Turn off auto summarization on routers N2 and B2.










 

Suggested Answer: D. Add wildcard masks to the network commands on routers N2 and B2.

Basically auto route summarization happens at the classful network boundary...so that would make N1 and B1 the locations that summarization would occur for the 172.16.0.0/16 classful networks.
So if you left auto-summarization enabled on those 2 routers, you would have an issue with discontiguous networks being advertised by both routers N1 and B1 with their classful mask (172.16.0.0/16 and 10.0.0.0/8), which will cause you issues.
Turning off auto-summarization on N2 and B2 wouldn't make any difference, as their networks wouldn't be summarized due to the fact that they are not meeting a classful boundary on their perspective routers. N1 will receive the 172.16.8.0/24 network from N2 with auto-summarization enabled.

This question is in 300-101 Cisco Implementing Cisco IP Routing (ROUTE) Exam
For getting Cisco Certified Network Professional (CCNP) Routing and Switching Certificate




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