Monitor Session - Cisco Catalyst 2950 Command Reference Manual

Chapter 2 Cisco IOS Commands
Command Modes
Global configuration
Command History Release
12.1(6)EA1
12.1(11)EA1
Usage Guidelines Traffic that enters or leaves source ports can be monitored by using SPAN or RSPAN. Traffic routed to
source ports cannot be monitored.
You can configure (and store in NVRAM) one local SPAN session or multiple RSPAN sessions on a
switch. The number of active sessions and combinations are subject to these restrictions:
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You can monitor traffic on a single port or on a series or range of ports. You select a series or range of
interfaces by using the [, | -] options.
If you specify a series of interfaces, you must enter a space after the comma. If you specify a range of
interfaces, you must enter a space before and after the hyphen (-).
EtherChannel ports cannot be configured as SPAN or RSPAN destination or reflector ports. A physical
port that is a member of an EtherChannel group can be used as a source or destination port. It cannot
participate in the EtherChannel group while it is configured for SPAN or RSPAN.
A port used as a reflector port cannot be a SPAN or RSPAN source or destination port, nor can a port be
a reflector port for more than one session at a time.
A port used as a destination port cannot be a SPAN or RSPAN source or reflector port, nor can a port be
a destination port for more than one session at a time.
You can enable 802.1X on a port that is a SPAN or RSPAN destination port; however, 802.1X is disabled
until the port is removed as a SPAN destination. (If 802.1X is not available on the port, the switch will
return an error message.) You can enable 802.1X on a SPAN or RSPAN source port.
Examples
This example shows how to create SPAN session 1 to monitor both sent and received traffic on source
interface 0/1 on destination interface 0/8:
Switch(config)# monitor session 1 source interface fastEthernet0/1 both
Switch(config)# monitor session 1 destination interface fastEthernet0/8
This example shows how to delete a destination port from an existing SPAN session:
Switch(config)# no monitor session 2 destination fastEthernet0/4
78-11381-05
Modification
This command was first introduced.
These RSPAN keywords were added: encapsulation, destination remote
vlan reflector-port, source remote vlan, all, local, remote.
SPAN or RSPAN source (rx, tx, both): one active session limit. (SPAN and RSPAN are mutually
exclusive on a source switch).
RSPAN source sessions have one destination per session with an RSPAN VLAN associated for that
session.
Each RSPAN destination session has one or more destination interfaces for each RSPAN VLAN that
it supports.
RSPAN destination sessions are limited to two, or one if a local SPAN or a source RSPAN session
is configured on the same switch.
Catalyst 2950 Desktop Switch Command Reference

monitor session

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