Users Guide

Remote port monitoring on VLT
In a network, devices congured with peer VLT nodes are considered as a single device. You can apply remote port monitoring (RPM) on
the VLT devices in a network.
In a failover case, the monitored trac reaches the packet analyzer connected to the TOR through the VLT interconnect link.
NOTE:
• In VLT devices congured with RPM, when the VLT link is down, the monitored packets might drop for some time. The time is
equivalent to the VLT failover recovery time (delay restore).
• ERPM does not work on VLT devices.
RPM on VLT scenarios
Consider a simple VLT setup where two VLT devices are connected using VLTi and a top-of-rack (TOR) switch is connected to both the
VLT peers using VLT LAGs in a ring topology. In this setup, the following table describes the possible scenarios when RPM is used to mirror
trac.
NOTE: The ports that are connected to the VLT domain, but not part of the VLT-LAG, are called orphan ports.
Table 2. RPM on VLT scenarios
Scenario Recommendation
Mirror an orphan port or VLT LAG or VLTi member port to VLT
LAG. The packet analyzer is connected to the TOR switch.
The following is an example of recommended conguration on the
peer VLT device:
1 Create RSPAN VLAN
!
interface vlan 100
no shutdown
remote-span
!
2 Create an L2 ACL for the RSPAN VLAN - RSPAN session and
attach it to VLTi LAG interface.
!
mac access-list rspan
seq 10 permit any any capture session 10
vlan 100
!
interface ethernet 1/1/1
no shutdown
switchport access vlan 1
mac access-group rspan in
!
3 Create a ow based RSPAN session on the peer VLT device to
monitor the VLTi LAG interface as source.
!
monitor session 10 type rspan-source
destination remote-vlan 100
flow-based enable
source interface ethernet1/1/1 (ICL lag
member)
!
Mirror a VLAN with VLTi LAG as member to any orphan port on the
same VLT device. The packet analyzer is connected to the local VLT
device through the orphan port.
The following is an example of recommended conguration on the
VLT device:
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