Reference Guide

Table 70. Troubleshooting VLT
Description Behavior at Peer Up Behavior During Run Time Action to Take
Bandwidth monitoring A syslog error message and an
SNMP trap is generated when
the VLTi bandwidth usage
goes above the 80%
threshold and when it drops
below 80%.
A syslog error message and an
SNMP trap is generated when
the VLTi bandwidth usage
goes above its threshold.
Depending on the traffic that
is received, the traffic can be
offloaded inVLTi.
Domain ID mismatch
The VLT peer does not boot
up. The VLTi is forced to a
down state.
A syslog error message and an
SNMP trap are generated.
The VLT peer does not boot
up. The VLTi is forced to a
down state.
A syslog error message and an
SNMP trap are generated.
Verify the domain ID matches
on both VLT peers.
Dell Networking OS Version
mismatch
A syslog error message is
generated.
A syslog error message is
generated.
Follow the correct upgrade
procedure for the unit with
the mismatched Dell
Networking OS version.
Remote VLT port channel
status
N/A N/A Use the show vlt detail
and show vlt brief
commands to view the VLT
port channel status
information.
Spanning tree mismatch at
global level
All VLT port channels go
down on both VLT peers. A
syslog error message is
generated.
No traffic is passed on the
port channels.
A one-time informational
syslog message is generated.
During run time, a loop may
occur as long as the mismatch
lasts.
To resolve, enable RSTP on
both VLT peers.
Spanning tree mismatch at
port level
A syslog error message is
generated.
A one-time informational
syslog message is generated.
Correct the spanning tree
configuration on the ports.
System MAC mismatch A syslog error message and an
SNMP trap are generated.
A syslog error message and an
SNMP trap are generated.
Verify that the unit ID of VLT
peers is not the same on both
units and that the MAC
address is the same on both
units.
Unit ID mismatch
The VLT peer does not boot
up. The VLTi is forced to a
down state.
A syslog error message is
generated.
The VLT peer does not boot
up. The VLTi is forced to a
down state.
A syslog error message is
generated.
Verify the unit ID is correct on
both VLT peers. Unit ID
numbers must be sequential
on peer units; for example, if
Peer 1 is unit ID “0”, Peer 2
unit ID must be “1’.
Version ID mismatch A syslog error message and an
SNMP trap are generated.
A syslog error message and an
SNMP trap are generated.
Verify the Dell Networking OS
versions on the VLT peers is
compatible. For more
information, refer to the
Release Notes for this
release.
VLT LAG ID is not configured
on one VLT peer
A syslog error message is
generated. The peer with the
VLT configured remains
active.
A syslog error message is
generated. The peer with the
VLT configured remains
active.
Verify the VLT LAG ID is
configured correctly on both
VLT peers.
VLT LAG ID mismatch
The VLT port channel is
brought down.
A syslog error message is
generated.
The VLT port channel is
brought down.
A syslog error message is
generated.
Perform a mismatch check
after the VLT peer is
established.
820 Virtual Link Trunking (VLT)