Source Vlans; Vlan Filtering - Cisco 3750G - Catalyst Integrated Wireless LAN Controller Configuration Manual

Chapter 28 Configuring SPAN and RSPAN
A source port has these characteristics:
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Source VLANs

VLAN-based SPAN (VSPAN) is the monitoring of the network traffic in one or more VLANs. The SPAN
or RSPAN source interface in VSPAN is a VLAN ID, and traffic is monitored on all the ports for that
VLAN.
VSPAN has these characteristics:
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VLAN Filtering

When you monitor a trunk port as a source port, by default, all VLANs active on the trunk are monitored.
You can limit SPAN traffic monitoring on trunk source ports to specific VLANs by using VLAN
filtering.
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It can be monitored in multiple SPAN sessions.
Each source port can be configured with a direction (ingress, egress, or both) to monitor.
It can be any port type (for example, EtherChannel, Fast Ethernet, Gigabit Ethernet, and so forth).
For EtherChannel sources, you can monitor traffic for the entire EtherChannel or individually on a
physical port as it participates in the port channel.
It can be an access port, trunk port, routed port, or voice VLAN port.
It cannot be a destination port.
Source ports can be in the same or different VLANs.
You can monitor multiple source ports in a single session.
All active ports in the source VLAN are included as source ports and can be monitored in either or
both directions.
On a given port, only traffic on the monitored VLAN is sent to the destination port.
If a destination port belongs to a source VLAN, it is excluded from the source list and is not
monitored.
If ports are added to or removed from the source VLANs, the traffic on the source VLAN received
by those ports is added to or removed from the sources being monitored.
You cannot use filter VLANs in the same session with VLAN sources.
You can monitor only Ethernet VLANs.
VLAN filtering applies only to trunk ports or to voice VLAN ports.
VLAN filtering applies only to port-based sessions and is not allowed in sessions with VLAN
sources.
When a VLAN filter list is specified, only those VLANs in the list are monitored on trunk ports or
on voice VLAN access ports.
SPAN traffic coming from other port types is not affected by VLAN filtering; that is, all VLANs are
allowed on other ports.
VLAN filtering affects only traffic forwarded to the destination SPAN port and does not affect the
switching of normal traffic.
Understanding SPAN and RSPAN
Catalyst 3750 Switch Software Configuration Guide
28-7