Implementing Cisco IP Routing (CCNP ROUTE, legacy) — Question 229

For a GRE tunnel to be up between two routers, which of the following must be configured?

Answer options

• A. Loopback Interface
• B. IP reachability between the loopback interfaces
• C. Dynamic Routing between routers.

Correct answer:

Explanation

For a GRE tunnel to be operational, there must be IP reachability between the loopback interfaces of the routers. While a Loopback Interface is often used, it is not strictly required, and Dynamic Routing can facilitate communication but doesn't guarantee the tunnel's establishment. Therefore, option B is the correct choice.