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Catalyst 6500 Series Switch Command Reference—Release7.6
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Chapter2 Catalyst 6500 Series Switch and ROM Monitor Commands set span
Usage Guidelines After you enable SPAN, system defaults are used if no parameters were ever set. I f y ou ch ange d
parameters, the old parameters are stored in NVRAM, and the new parameters are used.
Use a network analyzer to monitor ports.
If you specify multiple SPAN source ports, the ports can belong to different VLANs.
A maximum of two rx or both SPAN sessions and four tx SPAN sessions can exist simultaneously. If
you use a remote SPAN station, the maximum number of rx or both SPAN sessions is one.
Use the inpkts keyword with the enable option to allow the SPAN destination port to receive normal
incoming traffic in addition to the traffic mirrored from the SPAN source. Use the disable option to
prevent the SPAN destination port from receiving normal incoming traffic.
You can specify an MSM port as the SPAN source port. However, you cannot specify an MSM port as
the SPAN destination port.
When you enable the inpkts option, a warning message notifies you that the destination port d oes no t
join STP and may cause loops if this option is enabled.
When you configure multiple SPAN sessions, the destination module number/port number must be
known to index the particular SPAN session.
If you do not specify the keyword create and you have only one session, the session will be overwritten.
If a matching destination port exists, the particular session will be overwritten (with or without
specifying create). If you specify the keyword create and there is no matching destination port, the
session will be created.
If any VLANs on SPAN source port(s) are blocked by spanning tree, you may see extra pac kets
transmitted on the destination port that were not actually transmitted out of the source port(s). The extra
packets seen at the destination port are packets sent through the switch fabric to the source port and then
blocked by spanning tree at the source port.
Examples This example shows how to configure SPAN so that both 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
Enabled monitoring of Port 1/1 transmit/receive traffic by Port 2/1
Console> (enable)
This example shows how to set VLAN 522 as the SPAN source and port 2/1 as the SPAN destination:
Console> (enable) set span 522 2/1
Enabled monitoring of VLAN 522 transmit/receive traffic by Port 2/1
Console> (enable)
This example shows how to set VLAN 522 as the SPAN source and port 3/12 as the SPAN destination.
Only transmit traffic is monitored. Normal incoming packets on the SPAN destination port are allowed:
Console> (enable) set span 522 2/12 tx inpkts enable
SPAN destination port incoming packets enabled.
Enabled monitoring of VLAN 522 transmit traffic by Port 2/12
Console> (enable)
This example shows how to set port 3/2 as the SPAN source and port 2/2 as the SPAN destination:
Console> (enable) set span 3/2 2/2 tx create
Enabled monitoring of port 3/2 transmit traffic by Port 2/1
Console> (enable)