Specifications

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Catalyst 2950 and Catalyst 2955 Switch Command Reference
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Chapter 2 Cisco IOS Commands
monitor session
Defaults On a source interface, the default is to monitor both received and transmitted traffic. On source VLANs,
you can monitor only received traffic.
All VLANs are monitored on a trunk interface used as a source port.
If encapsulation type is not specified on a destination port, packets are sent in native form with no
encapsulation.
Command Modes Global configuration
Command History
Usage Guidelines Traffic that enters or leaves source ports or enters source VLANs can be monitored by using SPAN or
RSPAN. Traffic routed to source ports or source VLANs cannot be monitored.
You can set a maximum of two SPAN or RSPAN sessions. You can divide the two sessions between
SPAN, RSPAN source, and RSPAN destination sessions. Each session can have only one destination port
and only one transmitting source port. You can, however, have multiple receiving source ports and
VLANs.
You can monitor only received traffic on a VLAN; you cannot monitor transmitted traffic.
You can monitor traffic on a single port or VLAN or on a series or range of ports (ingress traffic only)
or VLANs. You select a series or range of interfaces or VLANs by using the [, | -] options.
If you specify a series of VLANs or interfaces, you must enter a space after the comma. If you specify
a range of VLANs or 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.
both, rx, tx (Optional) Specify the traffic direction to monitor. If you do not specify a
traffic direction, the source interface sends both transmitted and received
traffic. Transmitted (tx) traffic can be monitored on only one source port.
source remote vlan
vlan-id
Specify the source RSPAN VLAN for an RSPAN destination session.
source vlan vlan-id rx Specify the SPAN or RSPAN source interface as a VLAN ID. The vlan-id
range is 1 to 4094; do not enter leading zeros.
VLANs cannot be egress monitored. Direction (rx) must be specified.
all, local, remote Specify all, local, or remote to clear a SPAN or RSPAN session.
Release Modification
12.1(6)EA1 This command was first introduced.
12.1(11)EA1 These RSPAN keywords were added: destination remote vlan
reflector-port, source remote vlan, all, local, remote.