Concept Guide

Dell EMC Networking OS Behavior: All monitored frames are tagged if the congured 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 conguration source TenGig 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 dierence between the number of egress packets on the MD port and monitored packets on
the MG port.
Dell EMC Networking OS Behavior: The platform continues to mirror outgoing trac even after an MD participating in spanning tree
protocol (STP) transitions from the forwarding to blocking.
Conguring Port Monitoring
To congure port monitoring, use the following commands.
1 Verify that the intended monitoring port has no conguration 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 trac, as shown in the following example.
MONITOR SESSION mode
source
Example of Viewing Port Monitoring Conguration
To display information on currently congured port-monitoring sessions, use the show monitor session command from EXEC
Privilege mode.
DellEMC(conf)#monitor session 0
DellEMC(conf-mon-sess-0)#$source te 1/1 dest te 1/2 dir rx
DellEMC(conf-mon-sess-0)#show c
!
monitor session 0
source TenGigabitEthernet 1/1 destination TenGigabitEthernet 1/2 direction rx
DellEMC(conf-mon-sess-0)#
DellEMC(conf-mon-sess-0)#do show monitor session
SessID Source Destination Dir Mode Source IP Dest IP DSCP TTL Drop
Rate Gre-Protocol FcMonitor
------ ------ ------------ --- ---- --------- -------- ---- --- ----
---- ----------- ---------
0 Te 1/1 Te 1/2 rx Port 0.0.0.0 0.0.0.0 0 0 No N/
A N/A No
DellEMC(conf)#monitor session 0
DellEMC(conf-mon-sess-0)#source po 10 dest ten 1/2 dir rx
DellEMC(conf-mon-sess-0)#do show monitor session
SessID Source Destination Dir Mode Source IP Dest IP DSCP TTL Drop
Rate Gre-Protocol FcMonitor
------ ------ ----------- --- ---- --------- -------- ---- --- ----
---- ----------- ---------
0 Te 1/1 Te 1/2 rx Port 0.0.0.0 0.0.0.0 0 0 No N/
A N/A No
0 Po 10 Te 1/2 rx Port 0.0.0.0 0.0.0.0 0 0 No N/
A N/A No
750
Port Monitoring