Administrator Guide

Figure 88. Port Monitoring Configurations on the S-Series
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 TeGig 6/1 destination TeGig 6/2 direction tx, if the MD port TenGig 6/1 is an untagged member of
any VLAN, all monitored frames that the MG port TeGig 6/2 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.
Configuring Port Monitoring
To configure port monitoring, use the following commands.
1. Verify that the intended monitoring port has no configuration other than no shutdown, as shown in the following example.
EXEC Privilege mode
show interface
2. Create a monitoring session using the command monitor session from CONFIGURATION mode, as shown in the following
example.
CONFIGURATION mode
monitor session
monitor session type rpm/erpm
type is an optional keyword, required only for rpm and erpm
3. Specify the source and destination port and direction of traffic, as shown in the following example.
MONITOR SESSION mode
source
To display information on currently configured port-monitoring sessions, use the show monitor session command from
EXEC Privilege mode.
Dell(conf)#monitor session 0
Dell(conf-mon-sess-0)#$source ten 1/1 dest ten 1/2 dir rx
Dell(conf-mon-sess-0)#show c
!
monitor session 0
source TenGigabitEthernet 1/1 destination TenGigabitEthernet 1/2 direction rx
Dell(conf-mon-sess-0)#
Dell(conf-mon-sess-0)#do show monitor session
SessID Source Destination Dir Mode Source IP Dest IP
------ ------ ------------ --- ---- --------- --------
0 Te 1/1 Te 1/2 rx Port N/A N/A
Dell(conf)#monitor session 0
Dell(conf-mon-sess-0)#source po 10 dest ten 1/2 dir rx
Dell(conf-mon-sess-0)#do show monitor session
SessID Source Destination Dir Mode Source IP Dest IP
518
Port Monitoring