Explanation
Port mirroring is a method of monitoring network traffic by copying the data packets from one port to another port on the same switch or router. This allows the network security administrator to analyze the contents of the data sent between different networks without affecting the performance or security of the original traffic. Port mirroring can be configured to capture all traffic or only specific types of traffic, such as VLANs, protocols, or IP addresses.
References:
Port Mirroring - CompTIA Network+ N10-008 Domain 3.1 - YouTube1
CompTIA Network+ Certification Exam Objectives, page 142