Administrator Guide

VLT Fail-over Scenario
Consider a scenario where port monitoring is configured to mirror traffic on the source port or LAG of a VLT device to a
destination port on an other device on the network. A fail-over occurs when the primary VLT device fails causing the secondary
VLT device to take over. At the time of failover, the mirrored packets are dropped for some time. This time period is equivalent
to the gracious VLT failover recovery time.
RPM over VLT Scenarios
This section describes the restrictions that apply when you configure RPM in a VLT set up. Consider a simple VLT setup where
two VLT peers 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 restrictions that apply when RPM is used to mirror traffic:
Table 57. RPM over VLT Scenarios
Scenario RPM Restriction Recommended Solution
Mirroring an Orphan Port on a VLT LAG
— In this scenario, the orphan port on a
VLT device is mirrored to the VLT LAG
that connects a top-of-rack (TOR)
switch to the VLT device. The packet
analyzer is connected to the TOR
switch.
The bandwidth of the VLTi link is
unnecessarily used by mirrored traffic if
max rate limit value is configured in the
RPM mirror session.
Use ERPM session instead of RPM.
Mirroring an ICL LAG to Orphan Port —
In this scenario, the ICL LAG is mirrored
to any orphan port on the same VLT
device. The packet analyzer is connected
to the local VLT device through the
orphan port.
No restrictions apply. If the packet analyzer is directly
connected to the VLT device, use local
Port mirroring session instead of RPM.
Mirroring an ICL LAG to the VLT LAG —
In this scenario, the ICL LAG is mirrored
to the VLT LAG on the same VLT device.
Packet analyzer is connected to the
TOR.
No restrictions apply. None.
Mirroring VLT LAG to Orphan Port — In
this scenario, the VLT LAG is mirrored to
an orphan port on the same VLT device.
The packet analyzer is connected to the
VLT device through the orphan port..
No restrictions apply. If the packet analyzer is directly
connected to the VLT device, use local
Port mirroring session instead of RPM.
Mirroring using Intermediate VLT device
— In this scenario, the VLT device acts
as the intermediate device in remote
mirroring. The TOR switch contains the
source-RPM configurations that enable
mirroring of the VLT lag (of the TOR
switch) to any orphan port in the VLT
device. The packet analyzer is connected
through the VLT device, but not directly
to the VLT device.
No restrictions apply None.
Mirroring Orphan Ports across VLT
Devices — In this scenario, an orphan
port on the primary VLT device is
mirrored to another orphan port on the
secondary VLT device through the ICL
LAG. The port analyzer is connected to
the secondary VLT device.
No restrictions apply to the RPM
session. The following example shows
the configuration on the primary VLT
device:source orphan port
destination remote vlan
direction rx/tx/both.The
following example shows the
configuration on the secondary VLT
None.
632 Port Monitoring