Dell N3200-ON EMC Networking N-Series Switches CLI Reference Guide version 6.6 - Page 701

Bidirectional mirroring of multiple ports in a network may result in duplicate packets transmitted on the probe port (one copy for the receive side and another copy for the transmit side). Configuring the mirroring as rx only may help to reduce this issue. RSPAN VLANs must be configured with the remote-span command prior to configuration in an RSPAN session. RSPAN intermediate switches may also be configured with multiple sources feeding into an existing RSPAN VLAN. The source configuration requires an interface parameter, so traffic mirrored on the intermediate switch is not flooded across the entire RSPAN VLAN. Place probe ports upstream of the intermediate switch in this case. Configuring a second session on a source switch that mirrors RSPAN traffic from the reflector port is not supported. Configuring a second session on a source switch that mirrors an RSPAN source port to a local probe port is supported. VLAN mirroring is not recommended for RSPAN if sources on multiple switches are members of the VLAN. This is because, as stations communicate with each other over the mirrored VLAN, duplicate packets will be sent to the probe, once for the source port and once for each switch over which the packet is received in the source VLAN. For an enabled mirroring session, with a port-channel configured as the source interface, packets are mirrored only for the ports that are members of the port-channel at the time the mirroring session was enabled. Changes to the port-channel membership do not change the interfaces mirrored. Traffic is not mirrored for interfaces added to the port-channel, and is mirrored for ports removed from the port-channel. Specifically, to mirror interfaces added to an enabled port-channel, disable and re-enable the mirror session. Likewise, mirroring continues for ports removed from an enabled portchannel. Disable and re-enable the mirror session to stop mirroring on removed interfaces. Example This example shows how to configure a source switch using VLAN 723 as the destination RSPAN VLAN and Gi1/0/3 as the source interface. Te1/0/1 is configured as the reflector port. It is recommended that interface Te1/0/1 be configured as a trunk port. Interface Te1/0/1 must be configured as a member of VLAN 723 and may also carry traffic on other VLANs. No other interface should be configured as a member of VLAN 723. Layer 2 Switching Commands 701