Concepts

Mirrored Port and Observing Port

• Mirrored port: is a monitored port. All the packets that pass through a mirrored port are copied to the observing port.

• Observing port: is connected to a monitoring device and used to send packets from the mirrored port to the monitoring device.

  Generally, an observing port is only used to forward mirrored traffic, so it is recommended that other services be not configured on the observing port. If other services are configured on the observing port, mirrored traffic and traffic of other service may affect each other.

When mirroring is configured on the device, too many mirrored packets occupy much internal forwarding bandwidth and affect other services. Additionally, if the mirrored port and observing port provide different bandwidth, for example, 1000 Mbit/s on the mirrored port and 100 Mbit/s on the observing port, the observing port may fail to forward all mirrored packets in a timely manner because of insufficient bandwidth, leading to packet loss.

Mirroring Direction

The mirroring direction refers to the direction in which the device copies packets on the mirrored port to the observing port:

• Inbound: The device mirrors the packets that are received by the mirrored port to the observing port.
• Outbound: The device mirrors the packets that are sent from the mirrored port to the observing port.
• Bidirectional: The device mirrors the packets that are received and sent by the mirrored port to the observing port.