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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 24      Configuring SPAN and RSPAN
    Configuring SPAN
This example shows how to configure the destination port for ingress traffic on VLAN 5 by using a 
security device that does not support IEEE 802.1Q encapsulation.
Switch(config)# monitor session 1 destination interface fastethernet0/5 ingress vlan 5
This example shows how to configure the destination port for ingress traffic on VLAN 5 by using a 
security device that supports IEEE 802.1Q encapsulation.
Switch(config)# monitor session 1 destination interface fastethernet0/5 encapsulation 
dot1q ingress vlan 5
This example shows how to disable ingress traffic forwarding on the destination port.
Switch(config)# monitor session 1 destination interface fastethernet0/5 encapsulation 
dot1q
Step 3
monitor session session_number source 
interface interface-id [, | -] [both | rx | tx]
Specify the SPAN session and the source port (monitored port).
For session_number, specify 1.
For interface-id, specify the source port to monitor. Valid interfaces 
include physical interfaces and port-channel logical interfaces 
(port-channel port-channel-number).
(Optional) [, | -] Specify a series or range of interfaces. Enter a space 
before and after the comma; enter a space before and after the 
hyphen.
(Optional) Specify the direction of traffic to monitor. If you do not 
specify a traffic direction, the source interface sends both sent and 
received traffic.
• both—Monitor both received and sent traffic.
• rx—Monitor received traffic.
• tx—Monitor sent traffic.
Step 4
monitor session session_number 
destination interface interface-id 
[encapsulation {dot1q}] [ingress vlan 
vlan id]
Specify the SPAN session, the destination port (monitoring port), the 
packet encapsulation, and the ingress VLAN.
For session_number, specify 1.
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.
• dot1q—Use IEEE 802.1Q encapsulation.
(Optional) Enter ingress vlan vlan id to enable ingress forwarding 
and specify a default VLAN.
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.
Command Purpose