API Guide

Remote port monitoring on VLT
In a network, devices you configure 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 traffic reaches the packet analyzer connected to the top-of-rack (ToR) through the VLT
interconnect link.
NOTE:
● In VLT devices configured 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, the 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 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 you
use RPM to mirror traffic.
NOTE: Ports that connect to the VLT domain, but not part of the VLT-LAG, are called orphan ports.
Table 70. RPM on VLT scenarios
Scenario Recommendation
Mirror an orphan port or VLT LAG or VLTi member port to a
VLT LAG. The packet analyzer connects to the ToR switch.
The recommended configuration on the peer VLT device:
1. Create an RPM VLAN.
!
interface vlan 100
no shutdown
remote-span
!
2. Create an L2 ACL for the RPM VLAN - RPM session and
attach it to VLTi LAG interface.
!
mac access-list rpm
seq 10 permit any any capture session
10 vlan 100
!
interface ethernet 1/1/1
no shutdown
switchport access vlan 1
mac access-group rpm in
!
3. Create a flow-based RPM session on the peer VLT device
to monitor the VLTi LAG interface as the source.
!
monitor session 10 type rpm-source
destination remote-vlan 100
flow-based enable
source interface ethernet1/1/1 (ICL
lag member)
!
Mirror a VLAN with VLTi LAG as a member to any orphan port
on the same VLT device. The packet analyzer connects to the
local VLT device through the orphan port.
The recommended configuration on the VLT device:
522 Layer 2