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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Chapter 32 Configuring SPAN and RSPAN Configuring SPAN and RSPAN
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.
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.
Creating a Local SPAN Session
Beginning in privileged EXEC mode, follow these steps to create a SPAN session and specify the source
(monitored) ports or VLANs and the destination (monitoring) ports:
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 no monitor session {session_number | all
| local | remote}
Remove any existing SPAN configuration for the session.
For session_number, the range is 1 to 66.
Specify all to remove all SPAN sessions, local to remove all local
sessions, or remote to remove all remote SPAN sessions.
Step 3 monitor session session_number source
{interface interface-id | vlan vlan-id} [, |
-] [both | rx | tx]
Specify the SPAN session and the source port (monitored port).
For session_number, the range is 1 to 66.
For interface-id, specify the source port or source VLAN to monitor.
For source interface-id, specify the source port to monitor. Valid
interfaces include physical interfaces and port-channel logical
interfaces (port-channel port-channel-number). Vali d
port-channel numbers are 1 to 48.
For vlan-id, specify the source VLAN to monitor. The range is 1 to
4094 (excluding the RSPAN VLAN).
Note A single session can include multiple sources (ports or VLANs),
defined in a series of commands, but you cannot combine source
ports and source VLANs in one session.
(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 SPAN monitors both sent and received
traffic.
both—Monitor both received and sent traffic. This is the default.
rx—Monitor received traffic.
tx—Monitor sent traffic.
Note You can use the monitor session session_number source
command multiple times to configure multiple source ports.