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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 15 Configuring SPAN
Configuring SPAN
This example shows how to disable received traffic monitoring on port 1, which was configured for
bidirectional monitoring:
Switch(config)# no monitor session 1 source interface gigabitethernet0/1 rx
The monitoring of traffic received on port 1 is disabled, but traffic sent from this port continues to be
monitored.
Specifying VLANs to Monitor
VLAN monitoring is similar to port monitoring. Beginning in privileged EXEC mode, follow these steps
to specify VLANs to monitor:
To remove one or more source VLANs or destination ports from the SPAN session, use the no monitor
session session_number source vlan vlan-id global configuration command or the no monitor session
session_number destination interface interface-id global configuration command.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
no monitor session session_number
Clear any existing SPAN configuration for the session.
For session_number, specify 1 or 2.
Step 3
monitor session session_number source
vlan vlan-id [, | -] rx
Specify the SPAN session and the source VLANs (monitored VLANs).
You can monitor only received (rx) traffic on VLANs.
For session_number, specify 1 or 2.
For vlan-id, the range is 1 to 1005.
(Optional) Use a comma (,) to specify a series of VLANs, or use a
hyphen (-) to specify a range of VLANs. Enter a space after the comma;
enter a space before and after the hyphen.
Step 4
monitor session session_number
destination interface interface-id
[encapsulation {dot1q | isl}]
Specify the SPAN session and the destination port (monitoring port).
For session_number, specify 1 or 2.
For interface-id, specify the destination port. Valid interfaces include
physical interfaces.
(Optional) Specify the encapsulation header for outgoing packets. If
not specified, packets are sent in native form.
•
isl—Use ISL encapsulation.
•
dot1q—Use 802.1Q encapsulation.
Step 5
end
Return to privileged EXEC mode.
Step 6
show monitor [session session_number]
Verify your entries.
Step 7
copy running-config startup-config
(Optional) Save your entries in the configuration file.