B&B Electronics 516TX-A - Manual - Manual (Page 25)

(Revised 8/4/2009) 25
Switch Menu
Command Description
mirror Enable, disable, and configure port mirroring
trunking Enable, disable, and configure trunking
qos Enable, disable, and configure port or tagged Quality of Service
vlan Enable, disable, and configure Virtual Local Area Networks
igmp Enable, disable, and configure IGMP Snooping
filters Select traffic filter(s)
ports Reconfigure Individual Port Parameters
Port Mirroring
Mirroring allows the data exchange at one port (mirrored port, or source port) to be mirrored to another port
(monitor port, capture port, or destination port) where it can be recorded with a protocol analyzer, or other
analysis can be performed.
Command Description Comment
info Displays the current Mirroring settings.
disable (or enable) Enable Disable Mirroring Choice is opposite of current state
config Configure Port Mirroring. Select source and destination ports, and set
to mirror TX, RX, or Both.
Notes on Port Mirroring:
• A single port must be assigned as the source port. Any port in the switch may be chosen.
• A single port must be assigned as the destination port.
The choice is limited based on the source port. Entries are ranged to prevent issues. The destination
port must be in the same group as the source port, as below:
 1 through 8, and 25
 9 through 16
 17 through 24, and 26
This information is presented to the user on the CLI, as needed.
• There is a choice to Mirror (I)ncoming, (O)utgoing, or <(B)oth>.
‘Both’ is the default on just .
• N-View TM
frames are not mirrored.
Note:
With port mirroring enabled, the 500 series switch will forward the traffic (ingress, egress, or both) from the
source port to the destination port. Note that this results in mirrored packets being transmitted out the
destination port even though the source and destination addresses of that packet are not associated with that
port. This does not present a problem if the device attached to the mirror port is a PC.
However, if the mirror destination port is connected to another switch, that unit will learn and associate the
source address in the packet with that port. As a result, that switching device will block either incoming or
outgoing traffic (the opposite type of what was learned, as a protection mechanism to prevent loops).
Therefore, to monitor a mirrored port, it is best to directly connect a PC or network analyzer (sniffer) to the
mirror destination port, and not through a network.