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| 9.1 |  | Monitoring Switched Network Performance with SPAN and VSPAN |
| 9.1.3 |  | SPAN interaction with other features |

SPAN may affect the behavior of features configured on source and destination ports. SPAN disables some destination port features, which are restored when the SPAN session is removed from the switch.

SPAN interaction with VLANs and CDPs
Changes in VLAN membership can be made but will not be applied to SPAN destination ports. For source ports, VLAN or trunk settings take effect immediately, and the SPAN session automatically adjusts accordingly.

A SPAN destination port does not participate in CDP.

SPAN interaction with EtherChannel member or trunked ports
If a port is added to a monitored EtherChannel group, the new port is added to the SPAN source port list. If a port is removed from a monitored EtherChannel group, it is automatically removed from the source port list. If the port is the only port in the EtherChannel group, the EtherChannel group is removed from SPAN.

An EtherChannel group can be configured as a source port but not as a SPAN destination port. When a group is configured as a SPAN source, the entire group is monitored.

VLAN membership or trunk settings can be modified for source or destination ports at any time. However, changes in VLAN membership or trunk settings for a destination port do not take effect until the SPAN session is disabled.

If a physical port that belongs to an EtherChannel group is configured as a SPAN source, destination, or reflector port, that port is removed from the group. This topic is discussed in section 9.2. It is removed from the group. After the port is removed from the SPAN session, it rejoins the EtherChannel group. Ports removed from an EtherChannel group remain members of the group, but they are in the down or standalone state.

If a physical port that belongs to an EtherChannel group is a destination port and the EtherChannel group is a source, the port is removed from the EtherChannel group and from the list of monitored ports.

SPAN interaction with QoS classified and Multicast traffic
For ingress, or incoming, traffic monitoring, the packets sent to the SPAN destination port might be different from the packets actually received at the SPAN source port. The packets are forwarded after ingress QoS classification and policing. The Differentiated Services Code Point (DSCP) value of the sent packet might not be the same as the received packet.

Multicast traffic can be monitored. For egress, or outgoing, traffic and ingress port monitoring, only a single unedited packet is sent to the SPAN destination port. It does not reflect the number of times the multicast packet is sent.

A secure port cannot be a SPAN destination port.