Configure Port Mirroring

Before you begin

To change a port mirroring configuration, first disable mirroring.

About this task

Use port mirroring to aid in diagnostic and security operations.

Use port mirroring to make a copy of a traffic flow and send that copy to a device for analysis, for example, for diagnostic sniffing. Use the mirror to see the packets in the flow without breaking into the physical connection to place a packet onto the sniffer inline. You can also use port mirroring for security. You can send flows to inspection engines for post processing.

Connect the sniffer (or other traffic analyzer) to the output port you specify in this procedure.

Procedure

In the navigation pane, expand Configuration > Serviceability > Diagnostics.
Select General.
Select the Port Mirrors tab.
Select Insert.
To enable port mirroring for the instance, select the Enable check box.
Configure mirroring as required.
Note
- When you configure tx mode port mirroring on T-UNI and SPBM NNI ports, unknown unicast, broadcast and multicast traffic packets that ingress these ports and the system displays on the mirror destination port, although they do not egress the mirror source port. This is because tx mode port mirroring happens on the mirror source port before the source port squelching logic drops the packets at the egress port.
- The available four mirroring resources are shared between Fabric RSPAN and regular port mirroring, and are allocated based on the mode configured, Ingress (rx) or Egress (tx). Each configured mode occupies one mirroring resource, but when you configure the mode as both, it occupies two mirroring resources (one for Rx and one for Tx).
- Do not configure the source of mirrored traffic (mirroring to an I-SID) and the analyzer (monitoring an I-SID) on the same local device with the same I-SID offset. If you require mirroring and monitoring on the same local device, use standard port-based mirroring instead of Fabric RSPAN. Fabric RSPAN mirrors traffic into an I-SID of the SPB Fabric network and monitors traffic on the remote device; the network analyzer resides on the remote monitoring device and not on the same local device.
Select Insert.

Port Mirrors Field Descriptions

Use the data in the following table to use the Port Mirrors tab.


Name	Description
Id	Specifies an assigned identifier for the configured port mirroring instance.
MirroredPortList	Specifies a port to be mirrored (the source port).
Enable	Enables or disables this port mirroring instance. The default value is Enable.
Mode	Specifies the traffic direction of the packet being mirrored: tx mirrors egress packets. rx mirrors ingress packets. both mirrors both egress and ingress packets. The default is rx.
MirroringPortList	Specifies a destination port (the port to which the mirrored packets are forwarded). Configures the mirroring port.
MirroringMltId	Specifies the destination MultiLink trunking ID.
MonitoringIsidOffset	Used to configure the monitoring I-SID offset value. The offset ID is mapped to the actual monitor I-SID value to which the packets are mirrored.
MonitoringIsid	Specifies the actual monitor I-SID value to which the packets are mirrored.
MirroringQos	Used to define the Quality of Service (QoS) profiles for the mirrored packet into monitoring I-SID.