Cisco Certified Network Associate (CCNA) Practice Exam

What command helps identify the network topology when only a single router is accessible?

1. #show ip route

2. #show cdp neighbors

3. #show version

4. #show protocols

The correct answer is: #show cdp neighbors

The command that aids in identifying the network topology when only a single router is accessible is the one that shows detailed information about directly connected devices. Utilizing the command that displays neighboring devices in a Cisco environment is particularly effective in this scenario. This command leverages Cisco Discovery Protocol (CDP), which is a Layer 2 protocol that helps in discovering information about directly connected Cisco devices. By executing this command on a router, you can see a list of neighboring routers and switches along with details such as their device IDs, IP addresses, port identifiers, and capabilities. This is crucial for visualizing the immediate topology and understanding how devices are interconnected, even if other devices are not directly accessible. The other options provide valuable information but do not specifically focus on discovering neighbors in the same way. For example, the command that shows routing tables could inform you about the networks the router knows about, but not necessarily about the neighboring devices. The command providing device versioning will reveal details about the software and hardware, while the command for protocols highlights which protocols are running but lacks direct topology data. Thus, using the command associated with CDP yields the best insight into the network topology from a single router's perspective.