CCNA: Cisco Certified Network Associate — Question 230

Which statement about Cisco Discovery Protocol is true?

Answer options

• A. It is a Cisco-proprietary protocol.
• B. It runs on the network layer.
• C. It can discover information from routers, firewalls, and switches.
• D. It runs on the physical layer and the data link layer.

Correct answer: A

Explanation

The correct answer is A because Cisco Discovery Protocol is indeed a protocol developed and owned by Cisco. Option B is incorrect as it operates at the data link layer, not the network layer. Option C is misleading since it primarily discovers information from Cisco devices, not all routers and firewalls. Option D is also incorrect; while it operates at the data link layer, it does not run at the physical layer.