Administrator Guide

Figure 116. Port Monitoring Configurations
Dell Networking OS Behavior: All monitored frames are tagged if the configured monitoring direction is egress (TX), regardless of
whether the monitored port (MD) is a Layer 2 or Layer 3 port. If the MD port is a Layer 2 port, the frames are tagged with the VLAN ID of
the VLAN to which the MD belongs. If the MD port is a Layer 3 port, the frames are tagged with VLAN ID 4095. If the MD port is in a
Layer 3 VLAN, the frames are tagged with the respective Layer 3 VLAN ID. For example, in the configuration source PeGi 255/0/0
destination TenGigabitEthernet 0/23 direction tx, if the MD port PeGi 255/0/0 is an untagged member of any VLAN, all monitored
frames that the MG port PeGi 255/0/0 receives are tagged with the VLAN ID of the MD port. Similarly, if BPDUs are transmitted, the
MG port receives them tagged with the VLAN ID 4095. This behavior might result in a difference between the number of egress packets
on the MD port and monitored packets on the MG port.
Dell Networking OS Behavior: The platform continues to mirror outgoing traffic even after an MD participating in spanning tree
protocol (STP) transitions from the forwarding to blocking.
Important Points to Remember
• The destination interface should have no configurations except shutdown and no shutdown. By default, the "no ip address" must be
present. A MG/ destination port cannot be a member of a VLAN.
• The range command is supported in the source command to specify multiple source ports.
• You can enter multiple source statements in a monitoring session. A source port can be monitored by more than one destination
port.
• A destination port can be a physical or port-channel interface, and can be used in multiple sessions. A PE port or a VP lag cannot be
configured as a destination port.
• A maximum of 4 destination ports are supported per port pipe. For information about port pipes on the switch, see Port-pipes.
• Flow-based monitoring is supported on all types of source interfaces.
Examples of Port Monitoring
In the following examples of port monitoring, the four source ports 0/13, 0/14, 0/15, and 0/16 belong to the same port pipe and mirror
traffic to four different destinations (0/1, 0/2, 0/3, and 0/37).
You cannot add another destination on the same port pipe in a monitoring session because a maximum number of four destination ports
are supported on the same port pipe. If you configure another destination port on the same port pipe, a Syslog message is generated:
Unable to create MTP entry for MD interface MG interface in stack-unit stack-num port-pipe port-num.
Example of Changing the Destination Port in a Monitoring Session
Dell(conf)#mon ses 300
Dell(conf-mon-sess-300)#source tengig 0/17 destination tengig 0/4 direction tx
%Unable to create MTP entry for MD tenG 0/17 MG tenG 0/4 in stack-unit 0 port-pipe 0.
Dell(conf-mon-sess-300)#
Dell(conf-mon-sess-300)#source tengig 0/17 destination tengig 0/1 direction tx
Dell(conf-mon-sess-300)#do show mon session
SessionID Source Destination Direction Mode Type
--------- ------ ----------- --------- ---- ----
0 Te 0/13 Te 0/1 rx interface Port-based
10 Te 0/14 Te 0/2 rx interface Port-based
20 Te 0/15 Te 0/3 rx interface Port-based
30 Te 0/16 Te 0/37 rx interface Port-based
300 Te 0/17 Te 0/1 tx interface Port-based
Dell(conf-mon-sess-300)#
Port Monitoring
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