Enables monitoring of network traffic passing in or out of a network.

• A. Traffic Mirroring
• B. SPAN or Mirrored Port
• C. Local Traffic Mirroring
• D. Remote Traffic Mirroring

Answer: (A)

Duplicating the packets that traverse a network so a separate device can inspect them is the key idea. This is what traffic mirroring does: it copies traffic flowing in and out of a segment and sends those copies to a monitoring or analysis tool without interrupting the original flow. That makes it possible to observe, analyze, and troubleshoot network behavior, security events, or performance issues.

SPAN (Switch Port Analyzer) or Mirrored Port is a concrete way to implement this on a switch: you designate a port to receive the copies of the traffic from other ports. Local versus Remote Traffic Mirroring refers to where the monitoring tool sits relative to the device performing the mirroring—local on the same device or remote over the network. The broad capability described—enabling monitoring of traffic entering or leaving the network—fits best with traffic mirroring, since it covers all the ways traffic can be duplicated and forwarded to a monitoring point.