How Can Multiple Observing Ports Be Configured During Port Mirroring?

Publication Date:  2013-12-31 Views:  1773 Downloads:  0
Issue Description
The networking is as follows.
Alarm Information
None
Handling Process
The following provides a configuration example:
Reserve VLAN 3500.
#
vlan batch 3 10 20 100 300 to 301 3000 to 3002 3500 4000
#
Add an observing port to VLAN 3500.
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observe-port 1 interface GigabitEthernet0/0/21 vlan 3500
#
Configure three mirrored ports.
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interface GigabitEthernet0/0/3
port-mirroring to observe-port 1 both
#
interface GigabitEthernet0/0/4
port-mirroring to observe-port 1 both
#
interface GigabitEthernet0/0/5
port-mirroring to observe-port 1 both
#
Configure three observing ports.
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interface GigabitEthernet0/0/11
port link-type trunk
undo port trunk allow-pass vlan 1
port trunk allow-pass vlan 3500
#
interface GigabitEthernet0/0/12
port link-type trunk
undo port trunk allow-pass vlan 1
port trunk allow-pass vlan 3500
#
interface GigabitEthernet0/0/13
port link-type trunk
undo port trunk allow-pass vlan 1
port trunk allow-pass vlan 3500
#
Configure the loopback interface.
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interface GigabitEthernet0/0/21
description neibuhuanhui
loopback internal
mac-address learning disable
port link-type trunk
undo port trunk allow-pass vlan 1
port trunk allow-pass vlan 3500
stp disable
Root Cause
None
Suggestions
After packets on all mirrored ports are copied to an observing port, internal loopback is performed on the observing port. Then this observing port advertises the packets to other observing ports in the local VLAN. Before sending the packets out, the observing ports remove the VLAN tags from the packets.
Remarks: If the switch is configured with the stp enable command globally, you must run the stp disable command on the loopback interface; otherwise, when the loopback interface receives STP packets sent by itself, the interface enters the Discarding state and discards all incoming loopback packets.

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