Configuring Local Span; Span Configuration Guidelines; Creating A Local Span Session; Creating A Local Span Session And Configuring Ingress Traffic - Cisco Catalyst 3750 Software Configuration Manual

Configuring SPAN and RSPAN

Configuring Local SPAN

This section describes how to configure Local SPAN on your switch. It contains this configuration
information:
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SPAN Configuration Guidelines

Follow these guidelines when configuring SPAN:
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Catalyst 3750 Metro Switch Software Configuration Guide
21-10
SPAN Configuration Guidelines, page 21-10
Creating a Local SPAN Session, page 21-11
Creating a Local SPAN Session and Configuring Ingress Traffic, page 21-13
Specifying VLANs to Filter, page 21-15
You can configure a total of two local SPAN sessions or RSPAN source sessions on each switch. You
can have a total of 66 SPAN sessions (local, RSPAN source, and RSPAN destination) on a switch.
For SPAN sources, you can monitor traffic for a single port or VLAN or a series or range of ports
or VLANs for each session. You cannot mix source ports and source VLANs within a single SPAN
session.
The destination port cannot be a source port; a source port cannot be a destination port.
You cannot have two SPAN sessions using the same destination port.
When you configure a switch port as a SPAN destination port, it is no longer a normal switch port;
only monitored traffic passes through the SPAN destination port.
Entering SPAN configuration commands does not remove previously configured SPAN parameters.
You must enter the no monitor session {session_number | all | local | remote} global configuration
command to delete configured SPAN parameters.
For local SPAN, outgoing packets through the SPAN destination port carry the original
encapsulation headers—untagged, ISL, or IEEE 802.1Q— if the encapsulation replicate keywords
are specified. If the keywords are not specified, the packets are sent in native form. For RSPAN
destination ports, outgoing packets are not tagged.
You can configure a disabled port to be a source or destination port, but the SPAN function does not
start until the destination port and at least one source port or source VLAN are enabled.
You can limit SPAN traffic to specific VLANs by using the filter vlan keyword. If a trunk port is
being monitored, only traffic on the VLANs specified with this keyword is monitored. By default,
all VLANs are monitored on a trunk port.
You cannot mix source VLANs and filter VLANs within a single SPAN session.
Chapter 21 Configuring SPAN and RSPAN
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