Diagnosing Switch Problems Port Mirroring
OmniSwitch 6600 Family Network Configuration Guide April 2006 page 27-15
Creating a Mirroring Session
Before port mirroring can be used, it is necessary to create a port mirroring session. The port mirroring
source destination CLI command can be used to create a mirroring session between a mirrored (active)
port and a mirroring port. One port mirroring session is supported per OmniSwitch 6624, OmniSwitch
6600-U24, OmniSwitch 6600-P24, or OmniSwitch 6602-24 in a stack and up to two port mirroring
sessions are supported per OmniSwitch 6648 or OmniSwitch 6602-48 in a stack.
Note. To prevent the mirroring (destination) port from being blocked due to Spanning Tree changes, be
sure to specify the VLAN ID number (from 1 to 4094) for the port that will remain unblocked (protected
from these changes while port mirroring is active). This parameter is optional; if it is not specified,
changes resulting from Spanning Tree could cause the port to become blocked (default). See Unblocking
Ports (Protection from Spanning Tree) below for details.
To create a mirroring session, enter the port mirroring source destination command, and include the
port mirroring session ID number and the source and destination slot/ports, as shown in the following
example:
-> port mirroring 6 source 2/3 destination 2/4
This command line specifies mirroring session 6, with the source (mirrored) port located in slot 2/port 3,
and the destination (mirroring) port located in slot 3/port 4.
Note. Neither the mirrored nor the mirroring ports can be a mobile port. See Chapter7, “Assi gning Ports
to VLANs,” for information on mobile ports.
As an option, the same destination port can be shared by up to four sessions. In the following example
sessions 1, 5, and 6 mirror source ports 2/1, 2/2, and 2/3 on destination port 2/4:
-> port mirroring 1 source 2/1 destination 2/4
-> port mirroring 5 source 2/2 destination 2/4
-> port mirroring 6 source 2/3 destination 2/4
Unblocking Ports (Protection from Spanning Tree)
If the mirroring port will monitor mirrored traffic on an RMON probe belonging to a different VLAN than
the mirrored port, it should be protected from blocking due to Spanning Tree updates. To create a mirror-
ing session that protects the mirroring port from being blocked (default) due to changes in Spanning Tree,
enter the port mirroring source destination CLI command, and include the port mirroring session ID
number, source and destination slot/ports, and unblocked VLAN ID number, as shown in the following
example:
-> port mirroring 6 source 2/3 destination 2/4 unblocked 750