Configuring Span From The Cli - Cisco WS-C6506 Software Manual

Configuring SPAN on the Switch
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In software releases before software release 8.4(1), if you used the set span command without the create
Caution
keyword, and you had only one session configured, the session was overwritten. If two SPAN sessions
were already configured, you received an error message. If a matching destination port existed, the
particular session was overwritten (with or without specifying the create keyword). If you specified the
create keyword and there was no matching destination port, the session was created.
In software release 8.4(1) and later releases, the create keyword has been removed from the set span
command. When you enable a SPAN session without the create keyword, and another session is
available, the first session is not overwritten.

Configuring SPAN from the CLI

To configure SPAN, you specify the source, the destination ports, the direction of the traffic through the
source that you want to mirror to the destination ports, and if the destination port can receive the packets.
To configure a SPAN port, perform this task in privileged mode:
Task
Step 1 Configure the SPAN source and destination ports. set span {src_mod/src_ports | src_vlans | sc0}
Step 2 Verify the SPAN configuration.
If the SPAN destination port is connected to another device and you enable reception of the incoming
Caution
packets (using the inpkts enable keywords), the SPAN destination port receives the traffic for whatever
VLAN to which the SPAN destination ports belong. The SPAN destination port does not participate in
spanning tree for that VLAN. Use caution when using the inpkts keyword to avoid creating network
loops with the SPAN destination port or assigning the SPAN destination port to an unused VLAN.
This example shows how to configure SPAN so that both the transmit and receive traffic from port 1/1
(the SPAN source) is mirrored on port 2/1 (the SPAN destination):
Console> (enable) set span 1/1 2/1
Destination
Admin Source
Oper Source
Direction
Incoming Packets: disabled
Learning
Multicast
Filter
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If any of the VLANs on the SPAN source port(s) are blocked by spanning tree, you may see extra
packets that are transmitted on the destination port(s) that were not actually transmitted out the
source port(s). The extra packets are sent through the switch fabric to the source port and are blocked
by spanning tree at the source port.
: Port 2/1
: Port 1/1
: Port 1/1
: transmit/receive
: enabled
: enabled
: -
Chapter 49 Configuring SPAN, RSPAN and the Mini Protocol Analyzer
Command
{dest_mod/dest_port} [rx | tx | both]
[session session_number] [inpkts {enable |
disable}] [learning {enable | disable}]
[multicast {enable | disable}] [filter vlans...]
show span
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