In a CDP environment, what happens when the CDP interface on an adjacent device is configured without an IP address?
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A. B. C. D.C.
Although CDP is a Layer 2 protocol but we can check the neighbor IP address with the show cdp neighbor detail command.
If the neighbor does not has an IP address then CDP still operates without any problem.
But the IP address of that neighbor is not provided.
CDP ( Cisco Discovery Protocol) is a proprietary protocol that runs on Cisco devices to share information about the neighboring devices on the same network segment. It is enabled by default on most Cisco devices, including routers, switches, and access points.
When the CDP interface on an adjacent device is configured without an IP address, it means that the device does not have any IP address assigned to that interface. In this scenario, the CDP protocol will still continue to operate, and the neighbor device will still be discovered by the CDP-enabled device. However, the CDP information that is related to the IP address of the adjacent device will be missing.
Answer A: CDP becomes inoperable on that neighbor - This answer is incorrect because CDP will still operate, even if the adjacent device does not have an IP address assigned to the CDP-enabled interface.
Answer B: CDP uses the IP address of another interface for that neighbor - This answer is also incorrect because CDP does not use the IP address of any other interface on the adjacent device. If the adjacent device does not have an IP address assigned to the CDP-enabled interface, the IP address information will simply be missing.
Answer C: CDP operates normally, but it cannot provide IP address information for that neighbor - This answer is correct. When the CDP interface on an adjacent device is configured without an IP address, CDP will still operate normally, but it will not be able to provide any IP address information for that neighbor.
Answer D: CDP operates normally, but it cannot provide any information for that neighbor - This answer is incorrect. Even if the adjacent device does not have an IP address assigned to the CDP-enabled interface, CDP will still provide some information about the neighbor, such as its device ID, port ID, and device capabilities.
In conclusion, the correct answer is C. When the CDP interface on an adjacent device is configured without an IP address, CDP will operate normally, but it cannot provide IP address information for that neighbor.