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21-8
Catalyst 2950 Desktop Switch Software Configuration Guide
78-14982-01
Chapter 21 Configuring SPAN and RSPAN
Configuring SPAN
SPAN and RSPAN Session Limits
You can configure (and store in NVRAM) a maximum of two SPAN or RSPAN sessions on each switch.
You can divide the two sessions between SPAN, RSPAN source, and RSPAN destination sessions. You
can configure multiple source ports or source VLANs for each session.
Default SPAN and RSPAN Configuration
Table 21-1 shows the default SPAN and RSPAN configuration.
Configuring SPAN
This section describes how to configure SPAN on your switch. It contains this configuration
information:
• SPAN Configuration Guidelines, page 21-8
• Creating a SPAN Session and Specifying Ports to Monitor, page 21-9
• Removing Ports from a SPAN Session, page 21-11
• Specifying VLANs to Monitor, page 21-12
• Specifying VLANs to Filter, page 21-13
SPAN Configuration Guidelines
Follow these guidelines when configuring SPAN:
• SPAN sessions can coexist with RSPAN sessions within the limits described in the “SPAN and
RSPAN Session Limits” section on page 21-8.
• The destination port cannot be a source port; a source port cannot be a destination port.
• You can have only one destination port per SPAN session. You cannot have two SPAN sessions
using the same destination port.
• An EtherChannel port can be a SPAN source port; it cannot be a SPAN destination port.
• An 802.1X port can be a SPAN source port. You can enable 802.1X on a port that is a SPAN
destination or reflector port; however, 802.1X is disabled until the port is removed as a SPAN
destination or reflector port.
• For SPAN source ports, you can monitor transmitted traffic for a single port and received traffic for
a series or range of ports or VLANs.
Table 21-1 Default SPAN and RSPAN Configuration
Feature Default Setting
SPAN state Disabled.
Source port traffic to monitor Both received and sent traffic (both); for additional
source ports or VLANs, only received (rx) traffic can be
monitored.
Encapsulation type (destination port) Native form (no encapsulation type header).