Cisco Certified Network Associate (CCNA) Practice Exam

For EIGRP for IPv6 routers to become neighbors, which requirement must be met?

1. Same ASn, different K values, correct authentication

2. Same subnet, matching K values, incorrect authentication

3. Same ASn, matching K values, correct authentication

4. Different ASn, same K values, correct authentication

The correct answer is: Same ASn, matching K values, correct authentication

For EIGRP (Enhanced Interior Gateway Routing Protocol) to establish neighbor relationships between IPv6 routers, two fundamental requirements must be fulfilled: they must operate within the same Autonomous System (AS), and they must have matching K values. The K values represent the metrics that EIGRP uses to calculate routes; if these metrics do not match, routers cannot correctly interpret each other's routing information, preventing them from forming a neighbor relationship. Additionally, while having correct authentication can be important for the overall security and integrity of routing information, it is not a strict necessity for the formation of neighbor relationships. Thus, the critical components for EIGRP neighbors to form correctly are the same AS number and matching K values, which is why selecting the option that confirms these requirements is accurate.