Creating A Span Session And Specifying Ports To Monitor - Cisco Catalyst 2950 Software Configuration Manual

Configuring SPAN
•
•
•
•
•

Creating a SPAN Session and Specifying Ports to Monitor

Beginning in privileged EXEC mode, follow these steps to create a SPAN session and specify the source
(monitored) and destination (monitoring) ports:
Command
Step 1 configure terminal
Step 2 no monitor session {session_number | all |
local | remote}
Step 3
monitor session session_number source
interface interface-id [, | -] [both | rx | tx]
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
24-8
For SPAN source ports, you can monitor sent and received traffic for a single port or for a series or
range of ports.
When you configure a switch port as a SPAN destination port, it is no longer a normal switch port;
only monitored traffic passes through the SPAN destination port.
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 is enabled.
A SPAN destination port never participates in any VLAN spanning tree. SPAN does include BPDUs
in the monitored traffic, so any spanning-tree BPDUs received on the SPAN destination port for a
SPAN session were copied from the SPAN source ports.
When SPAN is enabled, configuration changes have these results:
If you change the VLAN configuration of a destination port, the change is not effective until
–
SPAN is disabled.
If you disable all source ports or the destination port, the SPAN function stops until both a
–
source and the destination port are enabled.
Purpose
Enter global configuration mode.
Clear any existing SPAN configuration for the session.
For session_number, specify 1.
Specify all to remove all SPAN sessions, local to remove all local
sessions, or remote to remove all remote SPAN sessions.
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.
Chapter 24 Configuring SPAN and RSPAN
78-11380-12